# What inserts do you like and why?



## Susquatch (Jun 29, 2022)

There are a lot of very knowledgeable people on here. A good thread on this topic would be appreciated. My eyes start glazing over when I read the insert company info pdfs and let's face it - they are biased to promote and sell their own products. I'd personally like to see something really simple. Something that members can contribute to in as much detail as they like. Everyone has their favorites, what are yours? What inserts do you reach for 90% of the time and how do you run them?

A good healthy debate on least costly, most available, best chip breaking, nicest cut, durability, etc. Of course, that should go hand in hand with a discussion of insert holders. 

I'm deliberately trying to avoid a list of manufacturers or links to their documents. These documents are great references but they are way too detailed, too much info, each one is different, and they often don't agree with each other. What I'm looking for in this thread is the kind of info your grandfather would give you about girls or tractors. 

I'm totally making this up but something like...... 

For mild steel Hexigon inserts are everywhere and they are very cost effective because...... They work best in these kinds of circumstances, and try to get some with this coating for plain steel, this for aluminium, this for cast iron, this for harder steels. Run em about sfm and this feet rate and this depth of cut and they will make you happy. You can get the holder at McDonald's for $x and they carry inserts at Burger King at 2 bucks each in a box of 10 or you can get them here on Aziton (link posted here) 

For Aluminium I like..... 

For Cast Iron I like.... 

What I'm thinking about here is something along the line of a member's favs for newbies and pros alike. Its a common question for new machinists. And even for the old hands, It's always good to see what others like and why. It's also good to see why other members might disagree and why. But mostly for beginners it's nice to get advice from experienced members instead of from the salesman at Busybee or Accusize. 

How many folks on here got sucked into buying a kit that came with a half dozen holders and inserts but now they can't get more inserts for and they never did use more than half the holders?

So ya, what are your own favorites and why?


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## Tom O (Jun 29, 2022)

I usually use mystery metal so if it cuts good I’m happy but for a known tougher metal I’ll take a cutter into ACT and tell them this is what I’m using and cutting.


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## David_R8 (Jun 29, 2022)

I'm also a member of Hobby Machinist and a member there wrote what I think is one of the best collections of insert information on the market.

Introduction to Indexable Tooling for the Metal Lathe: A User Guide





						Introduction to Indexable Tooling for the Metal Lathe: A User Guide: Best, David P.: 9798713564643: Books - Amazon.ca
					

Introduction to Indexable Tooling for the Metal Lathe: A User Guide: Best, David P.: 9798713564643: Books - Amazon.ca



					www.amazon.ca


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## Brent H (Jun 29, 2022)

@Susquatch: here is what I have to offer....

*LATHE SPECIFIC*: Inserts or indexable tools  .....well,  I only really have boring bars and threading tools with "carbide inserts".  Why?  ... cost and dedicated purpose.  For threading I have inserts for ACME and one single point holder (60*) but I typically use HSS and will usually grind a profile into HSS if required.  For "typical" left, right, straight tooling I use the carbide brazed to the holder:





These are easy to sharpen (diamond wheel for the carbide and under cut with regular stone) and last a long time, easy to profile and are reasonable cost compared to buying inserts.  

For the inserts used on the indexable tooling I will just get the cheapest on Amazon - if you search you can find quality ones (Iscar or ?) for reasonable and off you go.   

Speed and feed will get a decent finish and keep parts reasonable.  

@David_R8 : that book is like $150 - that is all the insert I might ever need ....LOL

Seriously for the "new lathe owner" - High speed steel- learn to sharpen, stone, hone and practice cuts.  kinda the same as welding - learn gas, TIG, Stick then MIG....

At this point in time I don't own any indexable insert tooling (other than boring bars and threading) for my lathes.....(sigh)........perhaps that is too much information..


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## SomeGuy (Jun 29, 2022)

As it stands, whatever I come across that is the right style tool for the job...I haven't gotten to the point of picking certain geometries.


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## David_R8 (Jun 29, 2022)

Brent H said:


> @Susquatch:
> 
> @David_R8 : that book is like $150 - that is all the insert I might ever need ....LOL
> 
> ...


Jeepers, when I bought it was only $50 CDN!
+1 to what Brent said about HSS.
With a sharp tool I can peel off .10" cuts on my South Bend 10K. No .10" is not a typo.


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## YYCHM (Jun 29, 2022)

HSS for me.  What carbide tooling I have (inserts/brazed) are just experiments.


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## Degen (Jun 30, 2022)

I use mostly inserts now and carbide on end mills, I try and choose what manufacturers recommend for the materials they are intended for as it achieves the best results.  If in doubt I use something designed for the toughest materials as the inserts and carbide last.  The drawback is surface finish sometimes is not the best.

Brazed carbide I have used but the disadvantage is you need diamond tooling and setup to sharpen them.  I no longer have any.

HSS I still use in both endmills and lathe tooling.  With mills I have a fair amount but requires certain expensive stones to sharpen correctly.  With lathe tooling it give me flexibility to grind one of cutting tools for one of cuts when it is needed.  Sometimes HSS is the most forgiving cutter in terms of usage and application on the lathe.


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## darrin1200 (Jun 30, 2022)

David_R8 said:


> I'm also a member of Hobby Machinist and a member there wrote what I think is one of the best collections of insert information on the market.
> 
> Introduction to Indexable Tooling for the Metal Lathe: A User Guide
> 
> ...





David_R8 said:


> Jeepers, when I bought it was only $50 CDN!
> +1 to what Brent said about HSS.
> With a sharp tool I can peel off .10" cuts on my South Bend 10K. No .10" is not a typo.


There is another paperback version available on a,a on for $75, but I don’t know what the difference is. 
There is also a kindle version for $10.


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## Susquatch (Jun 30, 2022)

Brent H said:


> @Susquatch: here is what I have to offer....
> 
> *LATHE SPECIFIC*: Inserts or indexable tools  .....well,  I only really have boring bars and threading tools with "carbide inserts".  Why?  ... cost and dedicated purpose.  For threading I have inserts for ACME and one single point holder (60*) but I typically use HSS and will usually grind a profile into HSS if required.  For "typical" left, right, straight tooling I use the carbide brazed to the holder:
> View attachment 24694
> ...



I loved this Brent. Whether you know it or not, I think you are highly respected by the members of this forum. Certainly by me. 

Your advice about first learning to use High Speed Steel is early in this thread and therefore likely to be seen by a newbie asking for info. Same goes for your advice about carbide. 

My first lathe had a lantern style tool post so HSS was really my only choice at the time. When I got my second newer lathe, the first thing I did was to get a carbide kit to go with it. Both the brazed style and the insert style. Both were dismal disappointments so I ran as fast as I could back to the comfort, safety, and satisfaction of HSS. As time passed, I slowly ventured back into the world of inserts and have been mostly happy. Mostly they are just sooooo convenient. But when the going is tough, or the job is critical, or the cutter shape is non-standard, I still reach for HSS. It never disappoints.


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## Susquatch (Jun 30, 2022)

I am happy to see how many members like and advocate HSS! 

Just saying that out loud, should bring the insert advocates out into the open, and chase the rest of us back into hiding!


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## Susquatch (Jun 30, 2022)

darrin1200 said:


> There is another paperback version available on a,a on for $75, but I don’t know what the difference is.
> There is also a kindle version for $10.



That's more like it.


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## Susquatch (Jun 30, 2022)

Degen said:


> Brazed carbide I have used but the disadvantage is you need diamond tooling and setup to sharpen them. I no longer have any.



I've never had a problem using a regular grinding stone. It's not fast or pretty and wears the stone quite fast, but it has worked for me. Maybe my stones are better than I thought they were!


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## 6.5 Fan (Jun 30, 2022)

I use HSS pretty much all the time, i have a insert type tool but it's use is infrequent.


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## Brent H (Jun 30, 2022)

@Susquatch : thank you for the compliments!

I can add to the conversation with this:

For the beginning person on the lathe:  Working with high speed steel and sharpening your own tooling gives you a lot more appreciation for how the tooling affects the material you are working with and how the geometry can improve or worsen the finish, cutting speed, depth of cut  etc.  Sharpening  your own cutters will also be necessary when it comes to profiling, threading, parting, trepanning etc or any possible "non standard" cutting on the lathe.  Grabbing an insert may not be possible, practical or affordable as using a high speed steel cutter.

The carbide tooling that is premade (not the indexable kind) also shows you profiles and cutter angles that you can readily use and get used to forming - this will help with HSS profiling for different materials.  The pre-made cutters are also good for use on harder materials and since you may not be cutting tool steels, or other harder material - say in the 41xx category, stainless type stuff all the time is is fairly inexpensive to have a few of these around.

Insert or indexable tooling has some distinct advantages but it all depends on a few things as to whether or not you can benefit from them.

Some things to think about:

A)  Insert tooling requires a specific holder for the insert.  That means you will require different holders for different inserts.  This can get expensive

B)  Inserts are typically designed with the intention of cutting specific material, at a specific speed and specific feed for the best finish.  Can your lathe achieve the specifications required to run the carbide efficiently and effectively?

C)  The index-ability of the tooling allows for the tools to be set up for CNC use and the inserts are designed with specifics - Like speed, feed, and wear rates so that a machine can achieve repeatability once a tool is set up.  Most of us "hobby" folks are a "one and done" type project people - Do you require that "quick change" or repeatability?  Sometimes it can be nice if you have a DRO

D) The world of carbide insert tooling is, to put it mildly, _freaking nut bar_!  There are literally  thousands of combinations of cutters, shapes, angles, qualities, tolerances, material specs etc.  You can easily go down the rabbit hole of tooling and never return!  I currently have several insert holders for my milling machine that I cannot seem to find the correct cutter for, inserts that measured correctly don't fit due to possibly the rake angle or they are a smidge to thick ...argh! frustrating

As a beginner on the Lathe it is important to learn the basics and get that down - how the machine works, speeds and feeds with cutters and materials you can screw up without injuring yourself or damaging your beautiful Lathe.  Become adept at different techniques and then see what you want to achieve.  If you are going to make something neato mosquito out of a different material and your lathe is up to the task of running the carbide inserts - well have fun and go for it, just realize that the insert tooling has a learning curve and may not be something everybody "needs".  Wanting......well that is different - LOL


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## Susquatch (Jun 30, 2022)

Brent H said:


> D) The world of carbide insert tooling is, to put it mildly, _freaking nut bar_! There are literally thousands of combinations of cutters, shapes, angles, qualities, tolerances, material specs etc. You can easily go down the rabbit hole of tooling and never return! I currently have several insert holders for my milling machine that I cannot seem to find the correct cutter for, inserts that measured correctly don't fit due to possibly the rake angle or they are a smidge to thick ...argh! frustrating



Great Addition @Brent H .

Regarding the above quote. As I said earlier, my first adventure with Carbide Inserts pretty much followed that formula. I'LL NEVER BUY A DISCOUNT KIT AGAIN. They are very attractive but IMHO, they suck. 

On the other hand, I think after you have "sort of" mastered your lathe or mill, I think one can successfully buy a few individual specialty holders and a few packages of inserts for them, if you are willing to do the research. By "sort of mastered", I don't mean mastered, I just mean that you are comfy warm about diving into a project without investing in an 33 video you tube series on how to cut a bar of a given diameter. 

If you buy a purpose driven holder, for a certain type of machining that you do a lot of, and you buy it knowing where to get inserts for it, and how to use it, I think carbide inserts can be a great tool in your arsenal. 

If for no other reason than that they are super convenient. It's hard to beat doing a BIG project from start to finish without having to worry about grinding any HSS tools. 

Note - I'll prolly come back here with a few of my favorites (both HSS and Carbide Inserts) after others have chimed in with theirs. For now, I feel like this thread has already served its purpose and that it will only get better as other experienced members chime in with their advice and favorite tools. In other words, the tone of this thread is already downright perfect for what I was after.


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## gerritv (Jun 30, 2022)

My approach is to use a consistent seller on Aliexpress, and look up the grades (of which there are usually only 3-5) for what they are suitable for.  That is why  I linked to https://www.machiningdoctor.com/grades/.

My tool holders are all 12x12, and are either CCMT06 or VCMT with some MGN200 for grooving/parting. By focusing on a few, I can afford to buy inserts for different materials, label the package and will soon add a SFM chart to each.

My threading inserts are all ER/IR11 A at present, with some AG 16's on the way (with new holders to match).
This is for a 1022 lathe, solid toolpost. 

I take deep cuts with carbide but not production level hogging. But I will admit to tripping the current overload on the input contactor at times.

For special jobs I regrind the relief for sharper edges and to shrink the tip radius. Working with <1mm diameter items requires a few diversions from standard.

My present fav source for the inserts is https://www.aliexpress.com/store/911783152, very predictable quality and brand name.

gerrit


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## Susquatch (Jun 30, 2022)

gerritv said:


> My approach is to use a consistent seller on Aliexpress, and look up the grades (of which there are usually only 3-5) for what they are suitable for.  That is why  I linked to https://www.machiningdoctor.com/grades/.
> 
> My tool holders are all 12x12, and are either CCMT06 or VCMT with some MGN200 for grooving/parting. By focusing on a few, I can afford to buy inserts for different materials, label the package and will soon add a SFM chart to each.
> 
> ...



Excellent @gerritv! I was hoping you would chime in with something JUST LIKE THAT. You DID NOT disappoint! 

Please come back and provide an update on the AG16s and holders after you have assessed them and are willing to recommend them - or willing to tell others to keep their distance! 

Thank you!


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## thestelster (Jun 30, 2022)

When turning or facing on the lathe, I use carbide inserts probably 70% of the time, and HSS the other 25%.  The carbide inserts that I use most often are CCMT and DCMT finishing inserts with the smallest nose radius available usually a -1 (1/64"), and to be used in positive rake tools.  The tool on the left is CCMT, the one on the right is DCMT.  The DCMT allows me to get in real close to tail stock when I'm using a center.

If I'm turning stock under 3/4", I'll use HSS.  But imagine turning 2" diameter stainless with HSS.  At 100rpm, I'd fall asleep!  But with carbide, 400rpm, I'm alert (especially with those hot yellow or blue chips bouncing off your bare flesh, and the smell of burning hair!!)


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## VicHobbyGuy (Jun 30, 2022)

gerritv said:


> My approach is to use a consistent seller on Aliexpress, and look up the grades (of which there are usually only 3-5) for what they are suitable for.  That is why  I linked to https://www.machiningdoctor.com/grades/.
> 
> My tool holders are all 12x12, and are either CCMT06 or VCMT with some MGN200 for grooving/parting. By focusing on a few, I can afford to buy inserts for different materials, label the package and will soon add a SFM chart to each.
> 
> ...


Thank you. Finally a response about inserts......


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## thestelster (Jun 30, 2022)

External threading on the lathe, I exclusively use carbide insert tooling.  The tool on the left, probably 98% of the time.  

For internal threading, anything larger than about 3/4" bore, I'll use carbide, and HSS for smaller bores.


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## thestelster (Jun 30, 2022)

For boring on the lathe, any bore larger than 5/8", carbide inserts, but with CARBIDE boring bars!!  Smaller bores, HSS.


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## thestelster (Jun 30, 2022)

Parting on the lathe:  carbide inserts.


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## Susquatch (Jun 30, 2022)

thestelster said:


> When turning or facing on the lathe, I use carbide inserts probably 70% of the time, and HSS the other 25%.  The carbide inserts that I use most often are CCMT and DCMT finishing inserts with the smallest nose radius available usually a -1 (1/64"), and to be used in positive rake tools.  The tool on the left is CCMT, the one on the right is DCMT.  The DCMT allows me to get in real close to tail stock when I'm using a center.
> 
> If I'm turning stock under 3/4", I'll use HSS.  But imagine turning 2" diameter stainless with HSS.  At 100rpm, I'd fall asleep!  But with carbide, 400rpm, I'm alert (especially with those hot yellow or blue chips bouncing off your bare flesh, and the smell of burning hair!!)



Thanks for chiming in. 

Excellent point about falling asleep. I never actually thought about that enough to add that factum to my deliberate choices. But the fact is that this is one of my reasons for choosing to use Inserts too. 

I try very hard not to have to turn things down excessively but sometimes you have no choice! I filled 3 garbage cans with swarf making one big pulley for a flail mower once. What a horrible tedious job. But a hundred times worse if I had to do it with HSS. There may be a few machinists around that do hogging cuts with HSS, but I'll bet most prefer a Carbide Insert for that work. In my case, it's not just the lathe speed, I also find I can use a bigger depth of cut with carbide too. 

Not all of us can peel off a tenth of an inch with carbide let alone with HSS like @David_R8 ....... .   Very impressed David! Glad you clarified that it wasn't a typo. Love to see a video clip of that happening! Your swarf must be deadly! No wonder you have no skunks......


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## LenVW (Jun 30, 2022)

I found a good website by MITSUBISHI Materials.
I copied the LINK and there are some great troubleshooting guides.

Carbide Inserts - Mitsubishi Materials Corp
-Nomenclature
-Basic information
-Applications
Most LINKs are functional once you agree to the terms.


Turning Inserts Identification | MITSUBISHI MATERIALS CORPORATION


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## Susquatch (Jun 30, 2022)

thestelster said:


> Parting on the lathe:  carbide inserts.



Hey @thestelster, since this thread is especially intended to help out the new machinists who visit here, could you please add the names of your holders and inserts and where you get them?


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## thestelster (Jun 30, 2022)

Milling:  I use this 1" diameter, 3 insert (R390) for almost everything.  Face milling, and side milling.  Obviously, I cannot plunge cut, so I use smaller solid carbide or HSS endmills for other operations.  The other is a 2" 4 insert for facing.


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## Dabbler (Jun 30, 2022)

Most of my insert tooling is for TCMT inserts.  It is what I started with, and I used non-ISO triangular inserts for years.  Kinnemetal has finally stopped making the inserts for my tooling, sio one day I will retool for CNMG tooling as well.  I still have quite a supply of the K inserts to use up first...

My go to on the miill is still HSS, however I recently acquired  a hundered or so all-carbide end mills to play with.  I'm hoping that they perform better than my HSS tooling... we'll see...


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## thestelster (Jun 30, 2022)

Susquatch said:


> Hey @thestelster, since this thread is especially intended to help out the new machinists who visit here, could you please add the names of your holders and inserts and where you get them?


Almost all my indexable tooling and inserts are Sandvik.  And I  get them from DGI Supply in Oakville, they use to be DoAll.  Sandvik tooling is pricey, but they are extremely well made, and last a lifetime.  The inserts are sold in packs of 10.


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## Dabbler (Jul 1, 2022)

@thestelster - Our Sandvik dealer in Calgary ignores you for any orders less than 1000$, and treats you poorly for orders less than 2000$.  The barrier to entry here is just too high.  I've tried to compare Sandvik to Kinnemetal 3 or 4 times in the last 40, but no go.


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## Tecnico (Jul 1, 2022)

Thanks @Susquatch for kicking this off, lots of good discussion so far.

I've relatively recently dipped my toe in the insert/indexable pond so I think I can add some comment from that perspective. Except for a brief introduction several years ago I had used a combination of HSS and brazed carbides over the years using lathes at previous employers, mostly after hours.

Fast forward to today and I’ve been using insert tooling for about 5 years. I have my personal lathe, a Myford S7 (1HP) for reference and I have tried out indexables for a few reasons. First, a lot of my tools, including my brazed carbides are a bit big for the tool post and center height becomes an issue, for the rest of the carbides I’d have to invest in a diamond wheel for the few that would fit the tool post (Dickson QC) so I might as well look to newer technology and indexables fitting the machine and see what they’re all about.

I bought a set of DCMT (7 deg positive, 55 deg rhombic shape insert, basically about a 2:1 diamond) tool holders to get started, they are 3/8” square shank so size code 06-2J:

SDJCR & L - (Right & Left)
SDNCN – Neutral/Straight orientation
SDUCR - Boring

I wasn’t impressed with the performance of the inserts that came with the tool holders so I proceeded to try and decipher the data tables in the Sowa catalogue for the inserts that Rideout Tools carry and order some better inserts. The easiest way to define the selection is to go to the catalogue section that covers the tool holder and see what insert options fit, then go to the insert tables. In my case, from the Sowa catalogue that is DCM(or G)T21.5X where X is the nose radius option. From there you choose material being worked, insert material and finish required.

The SOWA Canada catalogue is nice in that it also provides guidelines for feed and speed. It also has nice illustrated tables that define the “Turning Insert Code System” in both ANSI/inch and ISO/metric, page E6 – 7, similar to the Mitsubishi link @LenVW posted. With those codes you can jump from Mfr to Mfr. And cut through the marketing.

SOWA Catalog Ref

I bought some DCGT which do a beautiful job of producing a fine finish on aluminum (6061-T6) and a couple of other options which were tailored for steel and stainless steel. While doing better than the original inserts, they still cannot match the finish I can get in steel from a carefully ground and polished HSS tool. These are however my go to tools for every day steel/St-Stl because they’re fast to drop in place and don’t need adjustment for center height between setups. I even use the original inserts sometimes if it’s a quick & dirty job. Might as well get some use out of them!

That said, I’ve described what criteria I have to work with for the DCXT series my tool holders support but I’m very much interested in input from others about how to get a better finish on mild steel/stainless by using other insert types or perhaps by improved technique. Speeds/feeds/lubricants/polishing inserts?

I’m also interested in more discussion about insert parting tools. To date I have ground my own HSS parting blades with pretty good success but a drop in solution would be nice as an option.

Last up, since I’m relatively new to milling and now have my own mill (BP clone) I picked up a couple of insert EM tools for it. One is a ¾ dia., the other is ½” and both use APKT inserts. I picked up inserts for both steel & aluminum. I did a small job in steel the other day but haven’t tried the aluminum inserts yet.

I figured that given that the end mills that came with the machine are mostly a mish-mash of used and abused HSS I might as well try a couple of insert tools to use as every day work horses and save the good HSS I have for finish work.

To wrap up, I’m interested in advice from the experienced on using insert tooling for turning or milling that might not be obvious to someone who grew up on HSS & brazed carbide.

Thanks,

Tecnico 


P.S. While we’re at it, here is a link to a thread at Home Machinist in which “Harold_V” gives advice on grinding HSS tools:

Harold_V on grinding HSS

Complied as pdf:

Tool_Grinding_by_Harold_V

I haven’t read it through but the samples I have scanned seem to carry good advice.


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## Dabbler (Jul 1, 2022)

There are a few points about this topic best viewed from the 20,000 foot level:

1) Quality varies between manufacturers of both HSS and carbide.  
2) A high quality tool used in a way that it was not designed for may give very poor results despite its high quality.
3) the vast majority of carbide produced is for large, heavy machines that can exert more cutting pressure than is advisable for hobby sized machines.
4) Using random tooling from a variety of sources is more likely to give you randomized results - great for experimentation, but problematic for developing deeper understanding.

Because of these things, I started as a very newbie machinist with a very strict budget with a Kinnemetal holder and Kinnemetal inserts.  This was in the late 70s and offshore sources were not reliable or easy to find.  

This allowed me to compare notes in my light 12" lathe with my mentor and his heavy 15" lathe.  It also meant that when I broke an insert I knew absolutely that it was *my fault*, not a man7ufacturing defect, etc.  This was expensive in one way (about 200 1979 dollars), but very cheap instruction and learning.

-- let me say that I have *nothing* against offshore sources - I have several offshore holders and boxes of carbide.

One more 20,000 foot point:  For newbies - most carbide is cast, but not ground finished.  This leaves a very slight rounded (or dull, if you prefer) edge at the cutting surface.  This is intentional, and not a defect.  On larger lathes with greater cutting pressure, this profile gives longer service life and can actually improve the surface finish in some cases.  The additional pressure needed to cut in an industrial setting is still well within normal operating parameters.

*HOWEVER*  for smaller, less rigid (lathes especially) this can cause you a number of cutting headaches.

Here's how to 'fix' this problem:  If you look with a 20X loupe and see this rounding, ge a cheap set of diamond laps and hone then edge SLIGHTLY.  Don't mess with the cut angle or remove much material at all.  You will then notice significantly less cutting pressure and slightly improved cutting finish (if done correctly, yadda, yadda)

You can turn the cheapest cutter into a better one this way.

If you are lazy, then buy inserts that are ground and recommended to cutting aluminum.  They won't have as long a service life in steel, but will cut cleaner and with less pressure than a normal carbide insert.


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## thestelster (Jul 1, 2022)

Susquatch said:


> Hey @thestelster, since this thread is especially intended to help out the new machinists who visit here, could you please add the names of your holders and inserts and where you get them?


Almost all my indexable tooling and inserts are Sandvik.  And I get them from DGI Supply in Oakville, they use to be DoAll.  Sandvik tooling is pricey, but they are extremely well made, and last a lifetime.  The inserts are sold in packs of 10.


Dabbler said:


> @thestelster - Our Sandvik dealer in Calgary ignores you for any orders less than 1000$, and treats you poorly for orders less than 2000$.  The barrier to entry here is just too high.  I've tried to compare Sandvik to Kinnemetal 3 or 4 times in the last 40, but no go.


Hey, @Dabbler 
I can tell you, I don't order that much.  Usually $100-$300 per order.  I can't remember if I set up an account with DGI Supply, or just registered.  I order stuff on-line from there web site, and pay by credit card.  For inserts, you do have to buy a pack of 10, so depending on style, maybe $20-30 per insert.  I would think they would ship to Alberta.


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## David_R8 (Jul 1, 2022)

Susquatch said:


> Thanks for chiming in.
> 
> Excellent point about falling asleep. I never actually thought about that enough to add that factum to my deliberate choices. But the fact is that this is one of my reasons for choosing to use Inserts too.
> 
> ...


No video sadly but I'll see if I can find a pic of the chips.


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## VicHobbyGuy (Jul 1, 2022)

Dabbler said:


> If you are lazy, then buy inserts that are ground and recommended to cutting aluminum.  They won't have as long a service life in steel, but will cut cleaner and with less pressure than a normal carbide insert.


That's what I have done, for both turning inserts and also parting inserts. They work much better than the 'for steel' inserts with the rounded edges on my 7x14 lathe.


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## VicHobbyGuy (Jul 1, 2022)

thestelster said:


> For inserts, you do have to buy a pack of 10, so depending on style, maybe $20-30 per insert.


!!!!!!!!!!!!!!!!  We live in different universes.


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## Dabbler (Jul 1, 2022)

@VicHobbyGuy When I pay $14-20 for Kinnemetal inserts, they seem to last even longer per$ than most of the offshore inserts I have managed to buy.  I used one tcmt K insert for over a year before it was blown onm all 3 sides. (with periodic honing)  My offshore inserts seem to die by chipping or breaking.  If broken, I lose the other sides, etc.

BTW I still use offshore inserts regularly, but now fo lighter turning and odd jobs, and use name brand for accuracy and tougher steels.


----------



## thestelster (Jul 1, 2022)

Hi @VicHobbyGuy You're saying too expensive?  I've never used any inserts from China, so I can't/won't comment on them.  But I do know that these Sandvik inserts last a long time, gives me very good to excellent finishes (if using proper parameters), and I can have them in my hand within 2-3 days.  A pack of 10 will last me 3-4 years, and I use those CCMT inserts virtually every day. And I use the same grade on everything, steel, hardened steel, stainless, aluminium, and wood.  For the piece-of-mind, knowing that they perform, and the convenience of immediate delivery, and their longevity, I'm good paying extra, if I have to.


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## VicHobbyGuy (Jul 1, 2022)

thestelster said:


> Hi @VicHobbyGuy You're saying too expensive?


Most folks here seem to be serious and full time (?) machinists, in spite of the forum name. I'm just a hobbyist, so paying 2x what my lathe cost for a couple of toolholders and 2 packs of inserts would be silly. I make enough mistakes - both buying the wrong tools and then using them improperly - that I would never get 15 times the life out of a 'big name' tool vs something cheap from China. And, with minimum orders and shipping charges for the 'name brands', it is a factor of 15 or more in cost differential. I'm not making critical parts - just stuff for around the workshop and some little engine models- all just 'practice' and learning stuff.
As I said, different (but perhaps parallel?) universes.

@thestelster You use the same type/shape insert for every cut on every material- CCMT for everything, same tip radius and geometry, or just the same "grade' (quality)?


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## DPittman (Jul 1, 2022)

VicHobbyGuy said:


> Most folks here seem to be serious and full time (?) machinists, in spite of the forum name. I'm just a hobbyist, so paying 2x what my lathe cost for a couple of toolholders and 2 packs of inserts would be silly. I make enough mistakes - both buying the wrong tools and then using them improperly - that I would never get 15 times the life out of a 'big name' tool vs something cheap from China. And, with minimum orders and shipping charges for the 'name brands', it is a factor of 15 or more in cost differential. I'm not making critical parts - just stuff for around the workshop and some little engine models- all just 'practice' and learning stuff.
> As I said, different (but perhaps parallel?) universes.
> 
> @thestelster You use the same type/shape insert for every cut on every material- CCMT for everything, same tip radius and geometry, or just the same "grade' (quality)?


I'm just a hobbyist also and have had good luck (maybe ignorance is bliss) from inserts from Aliexpress and banggood.  They are radically so much cheaper than name brand ones that I'm okay taking a chance on the quality.  Someday I might try the expensive one but right now I don't think the inserts are my weakest link.


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## VicHobbyGuy (Jul 1, 2022)

DPittman said:


> I'm just a hobbyist also and have had good luck (maybe ignorance is bliss) from inserts from Aliexpress and banggood.  They are radically so much cheaper than name brand ones that I'm okay taking a chance on the quality.  Someday I might try the expensive one but right now I don't think the inserts are my weakest link.


As the saying goes: "That makes two of us!" 

Here's what I've been using lately for DCGT inserts:
https://www.aliexpress.com/item/4001128930528.html?





$10 for 10 inserts, including shipping.
I checked on the DGI website and the cheapest equivalent I saw was $17 EACH + taxes +shipping.
Fortunately Sandvik doesn't seem to make insert tools small enough to fit the OXA holder on my lathe, so I wasn't tempted by the $200 insert holders they produce.


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## Susquatch (Jul 1, 2022)

VicHobbyGuy said:


> Most folks here seem to be serious and full time (?) machinists, in spite of the forum name. I'm just a hobbyist, so paying 2x what my lathe cost for a couple of toolholders and 2 packs of inserts would be silly. I make enough mistakes - both buying the wrong tools and then using them improperly - that I would never get 15 times the life out of a 'big name' tool vs something cheap from China. And, with minimum orders and shipping charges for the 'name brands', it is a factor of 15 or more in cost differential. I'm not making critical parts - just stuff for around the workshop and some little engine models- all just 'practice' and learning stuff.
> As I said, different (but perhaps parallel?) universes.
> 
> @thestelster You use the same type/shape insert for every cut on every material- CCMT for everything, same tip radius and geometry, or just the same "grade' (quality)?



Boy, a lot of posts to reply to! That's what I get for spending the day out applying nitrogen to my corn......

No worries @VicHobbyGuy, I really do believe that the vast majority of members here really are hobbiests. I certainly consider myself a hobbiest. I also think we hobbiests all appreciate the views and help we get from the full time machinists even if we can't always afford to use what they use. 

When I started this thread, I wanted to get a full spectrum of input from everyone from beginners to pros. Those needing or wanting that information and advice will choose what they liked based on all the many factors that are important to them. Cost being a big one for me too. 

At some point, I will share my own favorites, some of which may already be obsolete given some of the great advice I've already seen here. 

So ya, it's all good.


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## Susquatch (Jul 1, 2022)

Dabbler said:


> @thestelster - Our Sandvik dealer in Calgary ignores you for any orders less than 1000$, and treats you poorly for orders less than 2000$.  The barrier to entry here is just too high.  I've tried to compare Sandvik to Kinnemetal 3 or 4 times in the last 40, but no go.



This is just sad. 



thestelster said:


> Almost all my indexable tooling and inserts are Sandvik. And I get them from DGI Supply in Oakville, they use to be DoAll. Sandvik tooling is pricey, but they are extremely well made, and last a lifetime. The inserts are sold in packs of 10.



A few years ago (pre covid) I asked my local supplier (Varco Industrial Supply) if they would consider stocking and selling smaller quantities of inserts than 10. They said they would consider it but only if it was a very popular item. I never explored it further. 

I like Varco. They are an expensive supplier, but if I want it NOW, they are only a half hour away. I buy lots of small stuff from them - eg can I have one 5/16 Dormer Drill please? They cater to the farming community and local industry. No big corporations around here. I walk through the door and they all treat me well. I cannot really complain about their high prices. It is what it is.


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## Susquatch (Jul 1, 2022)

Dabbler said:


> Here's how to 'fix' this problem:  If you look with a 20X loupe and see this rounding, ge a cheap set of diamond laps and hone then edge SLIGHTLY. Don't mess with the cut angle or remove much material at all. You will then notice significantly less cutting pressure and slightly improved cutting finish (if done correctly, yadda, yadda)
> 
> You can turn the cheapest cutter into a better one this way.
> 
> If you are lazy, then buy inserts that are ground and recommended to cutting aluminum. They won't have as long a service life in steel, but will cut cleaner and with less pressure than a normal carbide insert.



Two great pieces of advice. I recall you suggesting that inserts could be sharpened before. This is a great place to remind us of that. I must give that a try....... 

Btw, I always thought inserts were sintered, not cast. Learn something new every day! 

I have some aluminium inserts that I will try too.


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## VicHobbyGuy (Jul 1, 2022)

Susquatch said:


> At some point, I will share my own favorites, some of which may already be obsolete given some of the great advice I've already seen here.


I'm looking forward to it!  @gerritv gave some recommmendations which I appreciated. But generally folks seem to be 'holding their cards close to their vests'. I think it's pretty funny that the only specific insert info (DCGT070204-AK) is from me, since I am by far the least experienced and least competent person here!


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## Susquatch (Jul 1, 2022)

VicHobbyGuy said:


> I'm looking forward to it!  @gerritv gave some recommmendations which I appreciated. But generally folks seem to be 'holding their cards close to their vests'. I think it's pretty funny that the only specific insert info (DCGT070204-AK) is from me, since I am by far the least experienced and least competent person here!



Ya, sorry about that. It's not about holding any cards to the vest. It's about being old with a memory that never was any good for data points (names, numbers, etc) and getting the facts right. I gotta go to the shop and spend a few hours going through things, trying to remember where I got them, taking pictures, etc etc. 

I guess as the OP, I also wanted to let other people have their say first and I had lots to keep me busy in the meantime. But I got my fertilizing done today, so there is a good chance I'll get to it tomorrow. 

I may do what @thestelster did and break it into chunks too.


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## Dabbler (Jul 1, 2022)

Susquatch said:


> Btw, I always thought inserts were sintered, not cast. Learn something new every day!


I misspoke.  sintered.  not cast.


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## Tecnico (Jul 1, 2022)

Dabbler said:


> Here's how to 'fix' this problem:  If you look with a 20X loupe and see this rounding, ge a cheap set of diamond laps and hone then edge SLIGHTLY. Don't mess with the cut angle or remove much material at all. You will then notice significantly less cutting pressure and slightly improved cutting finish (if done correctly, yadda, yadda)


Interesting @Dabbler.  I had noticed that  the edges were not sharp feeling (DCMT) except for the DCGT and thought about dressing them but decided that the tool makers must know what they're doing......I'll have to try it.

I'm kind of surprised at how hard to deal with some of the suppliers west of here seem to be, I just pick up the phone to my local SOWA dealer, Rideout Tools (associated with KAR), and they sell me whatever I ask for in ones & twos which lets me try out a new insert and they don't charge a premium.  Maybe they'll ship 

D


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## thestelster (Jul 2, 2022)

VicHobbyGuy said:


> Most folks here seem to be serious and full time (?) machinists, in spite of the forum name. I'm just a hobbyist, so paying 2x what my lathe cost for a couple of toolholders and 2 packs of inserts would be silly. I make enough mistakes - both buying the wrong tools and then using them improperly - that I would never get 15 times the life out of a 'big name' tool vs something cheap from China. And, with minimum orders and shipping charges for the 'name brands', it is a factor of 15 or more in cost differential. I'm not making critical parts - just stuff for around the workshop and some little engine models- all just 'practice' and learning stuff.
> As I said, different (but perhaps parallel?) universes.
> 
> @thestelster You use the same type/shape insert for every cut on every material- CCMT for everything, same tip radius and geometry, or just the same "grade' (quality)?


Hi @VicHobbyGuy 
Yes, I only use those two insert shapes, CCMT, and DCMT for everything.  The DCMT for turning when using a center in the tailstock, and the CCMT for everything else. The coatings on my inserts are optimized for steel, but I use them for all metals, (I can't afford to have inserts with optimized coatings for different materials.)  And, I am not a machinist by profession.  But I machine in my profession, (I'm a gunsmith.) The insert holders I have are by Sandvik, and are 3/4" x 3/4".  And I've had them for at least 20 years, using them almost every day, and will probably last another 20.  Pretty cost effective I think.  I've attached some pictures of my turning tools, and the exact inserts I use.


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## thestelster (Jul 2, 2022)

When deciding on going carbide inserts, there are many factors that come into play. 
-insert shape
-material being machined
-hardness of material
-coatings
-finish i.e light finish to roughing

And machine ability:
-ridgidity
-horsepower
-speed

That is why it is imperative to search out all the information you can about a particular insert you want to use.  Companies like Sandvik, Kennametal, Mitsubishi and other top manufacturers, spend so much money on research and development.  Go into the website and get that information.  Without that knowledge, you're doing yourself a disfavor.  I've attached some info from an old Sandvik catalogue that I have, which helped me chose my inserts.


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## VicHobbyGuy (Jul 2, 2022)

Thanks for that info @thestelster . Really useful, and specific. I appreciate the time you took to do the scans and take pictures.

A couple of thoughts:

I haven't found manufacturer's online info very useful - and I've read/scanned that stuff a lot - each time till my eyes glazed over. Not surprisingly the manufacturers are providing info for their primary clients - production/manufacturing concerns, usually using CNC equipment and running everything on a 'time is money' basis - so high speeds and maximum cuts with powerful equipment. Just the opposite of the sort of stuff I do. A carbide insert for cutting steel with a minimum depth of cut of .015 or .025" isn't much use to me. So there's no way around that 'info' problem, other than asking other folks with low power and non-rigid machines (I won't use 'hobbyist' around here any more...  ) what works for them in cutting a variety of materials. There are many thousands of 7x lathes out there, so there would be a good small business opportunity for somebody -besides LittleMachineShop- to cater to that market. Even LMS is pretty useless for carbide insert info.

For beginners: The first step is to make sure that the insert holder will fit your toolpost and lathe, and then to make sure that you buy the correct size of insert. I have a pack of size 'ER16' threading inserts to remind me of that; I should have bought ER11s. Not a big loss at AliExpress prices. Some of the 'big name' companies don't seem to make holders with 8x8 mm or 10x10 mm shanks, so that helps to keep the choices in the budget department.  

This whole world of machine tool supplies reminds me a lot of the 'bad old days' before HomeDepot made plumbing and wiring suplies readily available to 'amateurs'. Before that, it was inflated prices and being treated like rubbish by the wholesale/retail supply places. Somebody here commented in the last few days that paying higher prices wasn't a problem, since it was tax-deductible (and possibly charged on to a customer?). You can certainly see the results of that situation at Grainger, KBC, etc. ...


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## Susquatch (Jul 2, 2022)

VicHobbyGuy said:


> Thanks for that info @thestelster . Really useful, and specific. I appreciate the time you took to do the scans and take pictures.
> 
> A couple of thoughts:
> 
> ...



Lotta truth in them there words......


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## Susquatch (Jul 2, 2022)

Ok, so here is page 1 of Susquatch's adventures. I'm gunna start with knurling cuz it's the easiest. 






IMHO, Left is nothing better than junk. Right is nothing to brag about, but it works. Left depends on toolholder pressure against the work. Right is independently clamped down onto the work as the knurl progresses. Left is big bucks junk, right is cheap but effective. Your mileage may vary.


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## Brent H (Jul 2, 2022)

@Susquatch : I have plans coming from England to build this:






I will be taking the left hand unit you show and chopping it up for use as the mounting arrangement and re-purposing the wheels for the unit itself.  I also have a couple sets of straight wheels that will go into play.  I will, of course, be posting the results of this build.

It is a Hemingway Kits model. - I just ordered the plans - not the materials


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## Susquatch (Jul 2, 2022)

Page 2 of Susquatch's Adventures. Parting.






This is a really nice tool. It was given to me by another member cuz it was a 1 inch tool. I milled the bottom off to fit my BXA Tool Post Holders

Here are the two styles of inserts I got for it.






I didn't get any aluminium inserts cuz aluminium is easy to part with almost anything.

This sucker works. And it works GREAT.

Before I got it, I used HSS with mixed results. Parting conventionally has always been a challenge.

The best solution which has NEVER FAILED ME, it to cut in reverse with an upside down parting tool. You can cut big, small, or whatever. It might make noise but it works. Here are two different types of HSS parting blade setups. Both are setup for parting upside down. I wonder why I have two holders setup that way.......








One is a T-Blade and the other a wedge blade. Both work fine in reverse. But worthy of note is the holder in the left photo. They work fine upside down but totally completely suck used conventionally. My advice is to avoid those adapter holders like the black plague.

One of these days, I will make a super rigid holder for parting. That will be a separate thread all of its own.

Here are a few special grinds I have done to try to part when the part didn't want to part.


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## Susquatch (Jul 2, 2022)

Page 3 of Susquatch's adventures is Turning with Inserts.

When I got the bigger lathe 10 years ago, I bought one of these kits. 






Do not waste your money. I only use one of them. The rest just gather dust. IMHO, buy a good one of whatever you think you need. It might cost as much as the whole set, but you will use it. 

Here is my favorite insert tool and inserts for it. 









I know, it's a trigon WCMT. Seems they are not very popular. But I like it for most insert turning. It has 3 working edges, does a good job of breaking chips and leaves a decent finish. Seems most users like the triangle inserts. I've never tried them, but plan to cuz it's hard to argue with popular. 

The other insert tools I use a lot are the round RMCT Inserts. 

They leave a great finish and are not very sensitive to feed and speed etc. You can see I use the small one a LOT. They also last forever cuz you can just turn it a bit for a fresh edge. 









I will do a separate page for HSS.


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## Tecnico (Jul 2, 2022)

Interesting about your experience with the knurling tools.  I have a J.H. Williams tool that came with my Myford and I've been happy with its performance.  I haven't tried one of the scissor versions and I looked at all the pinned hinges & joints in them (tolerance/alignment??) plus needing to clamp the wheels onto the work piece and didn't like the look of them!   

With a scissor I also wonder how you keep the correct crossover indexing distance between wheels to make the perfect knurl pattern?  With the Williams you have to knurl on a diameter incremented in 16ths to get a coherent cross over pattern.  

My Williams looks like this (photos from the web):


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## Tecnico (Jul 2, 2022)

Susquatch said:


> One of these days, I will make a super rigid holder for parting. That will be a separate thread all of its own.



@Susquatch  I wonder if you had a parting tool holder like this it would make parting with HSS blades more fun? I've used them on several machines and even on my light Myford it gives good results unless I try to do something dumb.

The holders you show don't look like they provide as secure/rigid/support on the parting blade letting it or the holder flex and nothing good comes from that, just ask me....


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## Susquatch (Jul 2, 2022)

Susquatch's Adventures Page 4 - Turning with HSS. 

Nobody should be surprised that I really like HSS turning. So many things you can do with it, so forgiving, so easy. 

Just learn to grind reliefs, nose radii, and buy decent blanks. 

At first I bought small 1/4" blanks cuz they were cheap. But other than a few special applications, I pretty much buy 1/2" and even 5/8" now. My BXA Tool Holders are 5/8.

All the reasons others like HSS apply to me too. I especially agree that learning to grind, understanding reliefs, cutting edges, nose radius, etc etc etc are all very valuable knowledge and skill sets. Despite using carbide inserts a fair bit, I do not advocate inserts for new machinists. There - I said it out loud. 

If a new machinist really wants to start turning before grinding, go get a set of these. The quality is great and they work right out of the box. This is probably my 4th set. 






And here is what I usually buy. I like 5% cobalt. It holds an edge much longer.






With that, here are a few examples of all the things you can do with HSS. Good luck finding comparable inserts. 

This is a special chamfer tool. It cuts a nice radius on the inside or outside of a tube or drilled or bored hole, or on a shoulder. 






This is a shear tool. It shaves the surface leaving behind a beautiful finish. 









And from left to right are: 

A really tough turning tool for bulk material removal. It looks rough and is rough, but the edges are well honed. This thing will take off a lot of metal very fast. Note the heavy top rake to bend the swarf out of the way. 

A really sharp pointed tool for getting into really tight places

A front end shear tool

A 45 degree chamfer tool - use forward or reverse to chamfer the edge you want. 

A deep inside threading/boring bar combo. (threading coming up soon). 

If you look closely at the second and third tool, you will see that they are shimmed to fit the tool holder more solidly and also to put the business end where I want it. 






Honestly, I cannot imagine life with a lathe without HSS. It does everything and anything. The tools don't need to be fancy. These are just the ones I use often enough to dedicate a holder to them.


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## Susquatch (Jul 2, 2022)

Tecnico said:


> Interesting about your experience with the knurling tools.  I have a J.H. Williams tool that came with my Myford and I've been happy with its performance.  I haven't tried one of the scissor versions and I looked at all the pinned hinges & joints in them (tolerance/alignment??) plus needing to clamp the wheels onto the work piece and didn't like the look of them!
> 
> With a scissor I also wonder how you keep the correct crossover indexing distance between wheels to make the perfect knurl pattern?  With the Williams you have to knurl on a diameter incremented in 16ths to get a coherent cross over pattern.
> 
> My Williams looks like this (photos from the web):



I have one very similar made by Armstrong. It worked ok on my old lathe. But not on the new one - mostly because it was intended to be used with a lantern style tool post. I like how both of ours pivot on the work.






The scissor knurler I have works great even though it is really really poorly made. Some things you just can't explain! The problem with the pressure type is the lateral force required to knurl the metal. The scissor type just floats with the work.

I can't wait to see @Brent H s when he gets it done. I suspect that there will be one just like it on my bench soon enough. I really don't like crap even if it does work..... LOL!


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## trlvn (Jul 2, 2022)

Brent H said:


> @Susquatch : I have plans coming from England to build this:
> 
> View attachment 24753
> 
> ...



Hi Brent:

I'm curious if you looked at Doug Gray's plans/kit:














						Heavy Duty Knurling Tool Drawings Only
					

Heavy Duty Knurling Tool Kit Drawings Only   The drawings only version of this product is a pdf digital download of the complete 16 page drawing package that include building notes and full scale templates of the plates. An immediate digital download so no waiting or postage.    Fantastic...



					d-gray-drafting-and-design.myshopify.com
				




If you compared them, what led you to choose the Hemingway?

Craig


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## Susquatch (Jul 2, 2022)

Tecnico said:


> @Susquatch  I wonder if you had a parting tool holder like this it would make parting with HSS blades more fun? I've used them on several machines and even on my light Myford it gives good results unless I try to do something dumb.
> 
> The holders you show don't look like they provide as secure/rigid/support on the parting blade letting it or the holder flex and nothing good comes from that, just ask me....
> 
> View attachment 24774



Yes, I have one just like that. I just didn't show it. And yes, it cuts a bit better than most. But not as good as upside down. 

I will be honest. Much as I like HSS, I don't think I will ever part with anything but a Carbide Insert again. That one I showed first up in my list is just amazing. I am not afraid to take the good where I find it even if it is different than what I always used to do. 

That said, one of my future projects is to make a parting tool holder that Bolts right to my compound just like the tool post. I need something that will part 6" diameter stock and carbide ain't gunna cut it. The alternative is a band saw of course but I have not figured out how to do the sequence. Anyway, that's a project for the future


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## Brent H (Jul 2, 2022)

@trlvn and @Susquatch: I chose the Hemingway (which is a copy of the Marlco brand).  The original was capable of knurling up to 4 or 6" depending how large you wanted to go.  The New version is scaled back to about 2-5/16"  max diameter.

You will note the lever on the side - this was part of my decision.  The lever operates a cam that engages or disengages the tool.  Basically use the lever to start and stop the knurl and also to increase the cut.  I have two of the Shite "press into the work ones" and therefore I have a couple sets of knurling wheels.  I also have wheels for making straight knurls so I am hoping to adapt that into the works - maybe even make 2 knurlers?  

The Hemingway one also represents more of a challenge to machine and that adds a bit more interest to making it.  There is an 8 part video series on a gentleman making his.  (youtube) You can buy the kit with the steel all included - Like 45 Pounds ish plus shipping.  The drawings were 16.5 pounds and 10 to ship - not cheap, but I figured it was worth a go - they mail you the drawings, I guess to keep it all on the up and up.


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## Susquatch (Jul 2, 2022)

Susquatch Adventures Page 5 - Boring bars.

So this is another area where I have come to love Carbide Inserts. In fact, with very few exceptions I seldom use HSS boring bars. One exception is the one above in HSS Turning. There are a few others.

The other thing about boring bars that breaks the pattern is that I actually do like the kits they sell.

Here is my favorite. Note how well used the bars all are as well as the fact that I use them enough to dedicate a tool holder to them. One is missing because I loaned it to a friend.






I have two other bars I really like. Both are tiny little things for boring small holes. This one is for 1/4 inch. I have an even smaller one for 0.2160 inch but like so many teeny tiny things, I couldn't find it for this post. It is solid carbide with no insert.

Edit - found it - photo added below. 












So ya, carbide insert boring bars are wonderful things AND in the case of boring bars, IMHO buying a set is a good economical way to get them. For boring bars, a set makes sense for lots of practical reasons IMHO.


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## Susquatch (Jul 2, 2022)

Susquatch Adventures Page 6 - threading.

First a confession, I LOVE THREADING. I don't even mind change gears to do it.

Second, another confession. I like using the 29.5 degree method.

Third, I have not yet tried a modern triangular insert to do it. I'd especially like to try one with a chip breaker.

I do use Carbide Inserts in the form of a Mesa Tool. It has both outside and inside threading inserts. Its a great tool, but not my favorite.






My favorite is actually a HSS insert tool by A R Warner. Yes, you read that correctly. It is a HSS Insert. It's sort of like the Mesa in that it is double ended. But the magic is that the inserts are HSS. Apparently, AR Warner is hard to reach right now. I don't know why. It's a small family business so who knows what tragedy has befallen them. I bought my first one from Brownells sold under their own Brownells brand,  but it's an Arthur Warner. You can get replacement inserts from Brownells too.  Like the Mesa, the Warner is double ended for inside and outside threading. But its a bit longer and fits a tool holder better. It's also a trigon style insert with three usable points. And because it is HSS, it can be sharpened - albeit very carefully.







I left this tool for the very last for a reason. It is my all-time most favorite turning tool of all. If something has happened to AR Warner and the tool disappears, I will feel like I lost a good friend.


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## Susquatch (Jul 2, 2022)

Brent H said:


> @Susquatch : I have plans coming from England to build this:
> 
> View attachment 24753
> 
> ...



I LOVE the idea of turning my expensive piece of junk into something gorgeous, useful, and functional like this.


----------



## thestelster (Jul 3, 2022)

VicHobbyGuy said:


> A carbide insert for cutting steel with a minimum depth of cut of .015 or .025" isn't much use to me. So there's no way around that 'info' problem, other than asking other folks with low power and non-rigid machines (I won't use 'hobbyist' around here any more...  ) what works for them in cutting a variety of materials.


Hi @VicHobbyGuy  you might not have to take that large of a cut.  If you look at the photo below, the blue area of the graph represents the working parameters of that insert.  So you could, theoretically take a .005" depth of cut at .006 in/rev feed.


----------



## Susquatch (Jul 3, 2022)

thestelster said:


> Hi @VicHobbyGuy  you might not have to take that large of a cut.  If you look at the photo below, the blue area of the graph represents the working parameters of that insert.  So you could, theoretically take a .005" depth of cut at .006 in/rev feed.



This is interesting to me @thestelster .  I had not noticed any inserts that could run that shallow. I especially noticed that they actually call this insert a finishing insert. 

I wonder if this insert will fit the two (left & right) CCMT holders in that useless kit of mine? If so, I'd be willing to give them a try. Not sure I feel inclined to buy new holders though...... 

I confess I still don't like the fact that they are not designed to take a smaller cut than 2 thou. I never did like taking a finishing pass over a thou. I like to sneak up on the desired dimension. That said, maybe @Dabbler s trick of honing inserts might make that possible. 

As always, I am not too old to learn new tricks.


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## Hacker (Jul 3, 2022)

gerritv said:


> My approach is to use a consistent seller on Aliexpress, and look up the grades (of which there are usually only 3-5) for what they are suitable for.  That is why  I linked to https://www.machiningdoctor.com/grades/.
> 
> My tool holders are all 12x12, and are either CCMT06 or VCMT with some MGN200 for grooving/parting. By focusing on a few, I can afford to buy inserts for different materials, label the package and will soon add a SFM chart to each.
> 
> ...


I use mostly carbide inserts and for profiles carbide brazed tools. My lathe came with a set of indexable tools and I was given a big box of use brazed inserts so I have stuck with that.
I find that I don't go through a lot inserts in the lathe but I manage to bugger up inserts on the mill as I am not very proficient with it yet. Part of the learning curve and the cost of education. 
I was buying my inserts from a supplier on Alibaba but they disappeared this winter so I have been looking around and will definitely check out your link. I am assuming they are real Sandvik/Mitsubishi and not knockoffs that many resellers seem to sell?
I do agree with Brent on how difficult it is trying to sort out carbide inserts. If I hadn't already had the tooling I would have gone with tool steel and brazed carbide.


----------



## Susquatch (Jul 3, 2022)

VicHobbyGuy said:


> So there's no way around that 'info' problem, other than asking other folks with low power and non-rigid machines (I won't use 'hobbyist' around here any more...  ) what works for them in cutting a variety of materials.



@VicHobbyGuy - I did a very informal assessment on my own of the members of the forum based on their usage of the forum and my impression of them as hobbiests or practicing machinists. There is a lot of water between those two bridges. But anyway, IMHO we really are mostly hobbiests. Even if you put a few members with other related professions in the pro group (which they might not agree with), I think it's a slam dunk that hobbiests dominate by a wide margin.

Of course, the definition of hobbiest could easily change that.

Looking in the mirror, I am retired but farming now. I got into machining to support my hobbies before I retired. But I didn't machine for a living then and don't now. Today, I do less machining to repair and modify farm machinery than I do to have pure fun in my shop, but even if not, nobody pays me to do that. And besides, even farming and machine repair is really about making my life richer and keeping me busy. There are a few members on here who are older than me, but I am mid-seventies so I'm old by any measure you want to use. I don't want to sit on a couch, watch tv, and die. So I fiddleFk with my machines, make tools for my tools, pursue my curiosity, help other members on the forum and get helped in return, and repair and modify farm machinery too.

So, in my heart of hearts, I am a hobbiest. What would you call me? Be careful how you answer that! LMAO!

Nonetheless, it's still a very good question. What do you think about starting a special thread with a survey and ask the active membership to self designate themselves?

Here is a screenshot of a proposed survey. What do you think? Is it worth doing? If so, can you suggest any improvements?


----------



## VicHobbyGuy (Jul 3, 2022)

Susquatch said:


> Nonetheless, it's still a very good question. What do you think about starting a special thread with a survey and ask the active membership to self designate themselves?
> 
> Here is a screenshot of a proposed survey. What do you think? Is it worth doing? If so, can you suggest any improvements?


Well, Jay Leno would call collecting cars a hobby, too.   
Perhaps a poll asking what it would cost to replace one's current shop equipment items (mills, shapers, lathes, drill presses, welding gear and all the tooling and supplies including meaasuring tools and materials and fasteners inventory) that support the 'hobby' would produce interesting reaults. From what I read here, $50k and up would be typical. That said, I'm in the 'burn that receipt before the CFO finds it' group, so don't expect an honest answer from me!


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## VicHobbyGuy (Jul 3, 2022)

Susquatch said:


> I confess I still don't like the fact that they are not designed to take a smaller cut than 2 thou. I never did like taking a finishing pass over a thou. I like to sneak up on the desired dimension. That said, maybe @Dabbler s trick of honing inserts might make that possible.
> 
> As always, I am not too old to learn new tricks.


Me, too. I liked @Dabbler's suggestion. But for me the whole point of insert tooling is to not bother with sharpening. Taking off enough carbide to get rid of that rounded cutting edge, by hand on my diamond plate, just seems like work.


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## Dabbler (Jul 3, 2022)

VicHobbyGuy said:


> Taking off enough carbide to get rid of that rounded cutting edge, by hand on my diamond plate, just seems like work.


My thought is when the carbide tooling has done some time and the cutting pressure increases a little,  One or 2 swipes with a diamond hone and they are like new again.  The trick is to not take much off, and make it as effortless as possible.  My hone is in a drawer right by the headstock of my 12X37 just for this purpose.  

I'm not advocating buying a cheap insert and rejigging them.  That is not worth the effort.


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## Susquatch (Jul 4, 2022)

VicHobbyGuy said:


> Well, Jay Leno would call collecting cars a hobby, too.
> Perhaps a poll asking what it would cost to replace one's current shop equipment items (mills, shapers, lathes, drill presses, welding gear and all the tooling and supplies including meaasuring tools and materials and fasteners inventory) that support the 'hobby' would produce interesting reaults. From what I read here, $50k and up would be typical. That said, I'm in the 'burn that receipt before the CFO finds it' group, so don't expect an honest answer from me!



Thank you for that comment. It helped me see the flaw in my thinking. I don't think how much money one has invested in their hobby is a meaningful qualification. In fact, I even think Jay Leno is indeed a hobbyist. 

I found this dictionary definition (the same across many dictionaries) to be most compelling: *A hobbyist, is “a person engaged in activities, in their spare time, that bring them pleasure.”* No place did any definition I found speak to money or even being paid. 

I also found this rather elegant and comprehensive on-line discussion about the difference between pros and hobbyists. It seems that you and I are not the only people interested in the issue. 






						What's the Difference Between a Hobbyist and a Professional? | Developer.com
					

In the Indianapolis market, I'm involved in a number of user groups, both formally and informally. Occasionally, we enter into discussions about what the




					www.developer.com
				




When the dust in my mind settled (lots of that in there), I decided to delete my proposed survey and move on. I think doing the survey would be divisive (us & them) and personally, I would rather be inclusive (all of us). If someone enjoys our hobby and is willing to give their time to help others, then I am simply grateful - I really don't care what their resources are. So I have no problem calling the vast majority of us hobbyists on here. But that doesn't mean I'm gunna run out and buy $200 inserts. In my dusty old mind, we can and do all have different value propositions that each of us needs to decide on our own based on our individual needs, budgets, and enjoyment. I guess I would also add that I think it's really great to get a wide range of advice to help me make those decisions - especially if it might be expensive!


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## Brent H (Jul 4, 2022)

@Susquatch : I wouldn't consider anyone a true "professional" at anything but rather a student of whatever passion they are pursuing.  You could argue that: say your "profession" is that of a Doctor.  Do you know all about being a doctor - no, so you are in a medical "practice".  Same with any other type of work, sport etc.  Some folks focus in on particular aspects of a profession and would be considered "Experts" by their peers in those particular aspects of the profession.

I would say the same for anyone on here that is working with various types of metal working.  Considering all the ways you can shape and form and bond things - crazy!  We are delving into the "profession of metal working" as students and perhaps experts in some areas.  You can call it a hobby, a passion, an interest or in some cases a need or desire, an aspiration,  a goal, an investment,  a money pit -- LOL


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## VicHobbyGuy (Jul 4, 2022)

I didn't express my thoughts very clearly, sorry about that. 
Anyway, back on topic..sorry about that sidetrack....

Yesterday I was boring a small hole in a bronze workpiece on the lathe and thought I would use one of the 'aluminum' inserts in the boring bar in place of the 'steel' type. I couldn't get the boring bar to fit the hole with the aluminum insert attached. With the cutting tip on center, the bottom of the bar was hitting the work. The aluminum inserts have an 'upsweep' at the tip which means that their effective thickness is greater. So that's something to consider, for me. I'll get some insert codes and perhaps a pic later to show what I mean.


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## Dabbler (Jul 4, 2022)

@VicHobbyGuy When I machine soft materials that can gaul, such as soft brass or some bronzes, I modify the twist drill or lathe tool to provide neutral rake.  A positive rake tool will 'bite' into the work.  This will cause problems hitting my dimension, poor finish and other unpleasant things. 

Most aluminum inserts have a positive rake, but for brass and copper I'd use a cheap braze-on, HSS, or hone an aluminum insert tip to be neutral or slightly negative rake.


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## Susquatch (Jul 4, 2022)

VicHobbyGuy said:


> Yesterday I was boring a small hole in a bronze workpiece on the lathe and thought I would use one of the 'aluminum' inserts in the boring bar in place of the 'steel' type. I couldn't get the boring bar to fit the hole with the aluminum insert attached. With the cutting tip on center, the bottom of the bar was hitting the work. The aluminum inserts have an 'upsweep' at the tip which means that their effective thickness is greater. So that's something to consider, for me. I'll get some insert codes and perhaps a pic later to show what I mean.



Most boring bars have a minimum ID Dimension for holes they can bore. And yes, some inserts increase that minimum dimension.

I have often ground away the bottom of a bar to get the required clearance. For a home ground bar it's no big deal. But it hurts a bit when you paid good money for the the bar.


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## Susquatch (Jul 4, 2022)

Brent H said:


> anyone a true "professional" at anything but rather a student of whatever passion they are pursuing. You could argue that: say your "profession" is that of a Doctor. Do you know all about being a doctor - no, so you are in a medical "practice". Same with any other type of work, sport etc. Some folks focus in on particular aspects of a profession and would be considered "Experts" by their peers in those particular aspects of the profession.



I always used to think that professionals were those who were licensed to practice in their profession. 

But the older I get the wider that definition gets...... Today, I think most people think anyone paid to do whatever they do is a professional. 

Sheesh.


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## DPittman (Jul 4, 2022)

Susquatch said:


> Today, I think most people think anyone paid to do whatever they do is a professional.


In my world and experience, the fact that one gets paid for the "work" they do definitely does not make one a "professional.  Just saying.


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## Susquatch (Jul 4, 2022)

DPittman said:


> In my world and experience, the fact that one gets paid for the "work" they do definitely does not make one a "professional.  Just saying.



So true. I was being sarcastic.


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## Dabbler (Jul 4, 2022)

My first 3 phase wiring job was to repair a failed install of a rotary 3 phase converter.  

The master electrician had wired it improperly and blew 2 or 3 of the capacitors inside the converter.  I rewired it from scratch, replace the components and it worked fin for 40 years.  In this case, I might be the professional, even though I wasn't paid for the work.  Certainly the guy who tried to bill for the work wasn't.  Unfortunately both the client and the master electrician were friends of mine, and I had recommended him for the job.  Very awkward.


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## Susquatch (Jul 4, 2022)

Dabbler said:


> Very awkward.



I wish the forum allowed multiple emoticons...... Lots of content in that post!


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## thestelster (Jul 4, 2022)

Susquatch said:


> Most boring bars have a minimum ID Dimension for holes they can bore. And yes, some inserts increase that minimum dimension.
> 
> I have often ground away the bottom of a bar to get the required clearance. For a home ground bar it's no big deal. But it hurts a bit when you paid good money for the the bar.


I've had to grind the heads of some boring bars as well, with small boring bars it's _de rigueur_.   You can also raise the bar, but then rotate it so that the tip of the insert is on center.  This also gives you added clearance below the tip.


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## Tom O (Jul 4, 2022)

I would think that hobbiest would be something like without papers whereas a professional has his papers to prove his training. I belive this can be proved by the option of challenging the course to receive your papers.


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## David_R8 (Jul 4, 2022)

I think separating remuneration from certification is important to this way off-topic discussion 
For example an amateur athlete vs a professional athlete is about remuneration and not certification.
Whereas a certified electrician/engineer/dentist/doctor can do work for free and it has no bearing on the status of their certification.


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## VicHobbyGuy (Jul 4, 2022)

Dabbler said:


> @VicHobbyGuy When I machine soft materials that can gaul, such as soft brass or some bronzes, I modify the twist drill or lathe tool to provide neutral rake.


Thanks, Dabbler. I have a duplicate set of drills just for brass (and aluminum, too as it can be as 'grabby' as brass) that I've slightly modified - they definitely do work better. I was surprised how much better the 'for aluminum' inserts worked on bronze and brass than what I'd been using, and they do stay sharp. But I'll try your suggestions.


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## VicHobbyGuy (Jul 4, 2022)

Susquatch said:


> I have often ground away the bottom of a bar to get the required clearance. For a home ground bar it's no big deal. But it hurts a bit when you paid good money for the the bar.


Well, it was good money, but very little of it.  Probably $10 from AliExpress. I ground away as much as I dared, then decided to switch to a home ground HSS boring bar made from a 6mm (?) HSS round blank (also from AliExpress). And, no, I'm not posting a pic of that one-it's really crude but it got the job done with a lot of light passes.


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## Susquatch (Jul 5, 2022)

VicHobbyGuy said:


> Well, it was good money, but very little of it.  Probably $10 from AliExpress. I ground away as much as I dared, then decided to switch to a home ground HSS boring bar made from a 6mm (?) HSS round blank (also from AliExpress). And, no, I'm not posting a pic of that one-it's really crude but it got the job done with a lot of light passes.



Aw, come on..... Post a pic! I'll show you mine if you show me yours! LMAO!  Ya, we all have our uglies. Lots of light passes with an ugly piece of home ground HSS is often the secret to a great result! Glad it worked out!


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## Canadium (Jul 27, 2022)

Sorry to get in on this thread so late. This discussion has provoked me to examine more closely what I already have and to study up some more on indexable tooling. I've been wanting to get the aforementioned book by David Best for a long time. Now I finally have it in hand.

The tooling I have is all what I would call "legacy" tooling; ie it came with my lathe. It was assembled by a professional machinist so any semblance of intelligent choices was not my doing. Although in my estimate the quality is top notch the problem is it's very old. Many of the holders are by Valenite which was a North American manufacturer no longer in existence. Some of the inserts used may no longer be made either although I suspect substitutes probably exist. (a number of inserts were also included so in some cases the holder came with a supply that will last my lifetime in any case) This all however compounds the complexity of the question; are these tools useable and what others would complement this collection? In particular there is only one indexable boring bar of 3/4 inch diameter (by Kennametal). A few HSS bars were included. I'm thinking some more indexable boring bar sizes might be a good idea.

What do you all think? What other tooling would you recommend to add to this collection???


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## VicHobbyGuy (Jul 27, 2022)

Canadium said:


> What do you all think? What other tooling would you recommend to add to this collection???


Do you have a collection of HSS tools as well? I'm a complete beginner, but I wouldn't want to give up my A.R. Warner HSS parting blade (.040" ?). My insert parting tool can't reach very far into a workpiece, and it's wider.

I have a very small 7x lathe, and I find that the 'for aluminum' inserts work better for me, even on steel since they are sharp enough to take light cuts.


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## Susquatch (Jul 27, 2022)

VicHobbyGuy said:


> A.R. Warner HSS parting blade (.040" ?).



AR Warner makes a parting tool? I'm VERY interested! 

Can you post a few photos? 

Btw, I heard they are not answering calls or emails right now. It's a small family business. I hope they are ok.


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## David_R8 (Jul 27, 2022)

Susquatch said:


> AR Warner makes a parting tool? I'm VERY interested!
> 
> Can you post a few photos?
> 
> Btw, I heard they are not answering calls or emails right now. It's a small family business. I hope they are ok.











						Kit #29 1/2 inch Parting Tool
					





					www.arwarnerco.com


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## VicHobbyGuy (Jul 27, 2022)

Susquatch said:


> AR Warner makes a parting tool? I'm VERY interested!


https://littlemachineshop.com/products/product_view.php?ProductID=1729&category=


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## Susquatch (Jul 27, 2022)

David_R8 said:


> Kit #29 1/2 inch Parting Tool
> 
> 
> 
> ...



Interesting. A little different than the norm. Most of this kind have a T-bar type affair that sits in the tool holder with the parting blade held outside. I don't like these - they are short on rigidity. This looks promising. The tool holder clamps the tool holder!


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## Canadium (Jul 27, 2022)

VicHobbyGuy said:


> Do you have a collection of HSS tools as well? I'm a complete beginner, but I wouldn't want to give up my A.R. Warner HSS parting blade (.040" ?). My insert parting tool can't reach very far into a workpiece, and it's wider.
> 
> I have a very small 7x lathe, and I find that the 'for aluminum' inserts work better for me, even on steel since they are sharp enough to take light cuts.



This shows most of my HSS bits for both my small and my larger lathes. This again is "legacy tooling" that came with my machines.


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## Susquatch (Nov 14, 2022)

@David_R8 posted the following info about his favorite inserts on another thread. 



David_R8 said:


> One minor bit of advice on insert tooling @curmudgeon
> I have a set of import tool holders and associated inserts. The tool holder are generally OK but the inserts are about as durable as crackers. I splurged and bought a brand name tool holder and inserts and noticed a really big difference in cut quality and durability.
> I can't seem to access my KBC acount at the moment or I'd give you part numbers.





David_R8 said:


> Alrighty, managed to get back into my KBC account.
> This is the tool holder: https://www.kbctools.ca/itemdetail/1-428-103237
> And these are the inserts: https://www.kbctools.ca/itemdetail/1-244P-931


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## Canadium (Nov 14, 2022)

I just made reference to Stephan Gotteswinter's Shop Tour video in another thread. This same video also was the source for another seemingly earth moving revelation for me. He states there between the 51 and 54 min marks that there is no longer any need for HSS. "Carbide is it". He gets around the limitations of carbide inserts by modifying the inserts (or worn out solid carbide cutters) on a grinder. The result surpasses anything that can be done with HSS according to Stephan.


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## Dabbler (Nov 14, 2022)

I've been resharpenng inserts for years - it works very well.  The edge the you make with hand grinding is more fragile and breaks down quicker than a factory edge, but it is sure worth it!

When you have a 15$ Kennemetal insert, it is a nice bonus to get twice the cutting time on it.


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## VicHobbyGuy (Nov 14, 2022)

> And these are the inserts: https://www.kbctools.ca/itemdetail/1-244P-931



It would be interesting to see a head-to-head test between these KBC Korloy inserts and the same (?) "Korloy" inserts from AliExpress, since there's a 10x difference in price between the two.

Thinking about the Gotteswinter statement about (modified) carbide inserts: it has been mentioned before that using the  'for aluminum' carbide inserts can work quite well for small lathe/hobby users. The cost (from AliExpress,not KBC!) is not much, so perhaps worth an experiment.


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## Susquatch (Nov 14, 2022)

Canadium said:


> He states there between the 51 and 54 min marks that there is no longer any need for HSS. "Carbide is it".



Gotteswinter just crapped in his own porridge in my books. Although I agree with the value of Carbide inserts and also in the merits of reworking them, I cannot even remotely subscribe to the idea of dumping HSS completely. 

Lost my appetite for porridge too.


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## Dabbler (Nov 14, 2022)

Susquatch said:


> I cannot even remotely subscribe to the idea of dumping HSS completely.


His context is that of a commercial user.  Even his home shop is now primarily a job shop, and more than half his income derives from it.  He has gone to part time a Bosh Electronics, where he works.

For a hobby shop there's nothing like HSS, especially in those sub-1-hp lathes and mills.  Somewhere around 3HP, carbide seems to gain the upper hand.  Even on my 7HP lathe HSS has a role.


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## Canadium (Nov 14, 2022)

Dabbler said:


> I've been resharpenng inserts for years - it works very well.  The edge the you make with hand grinding is more fragile and breaks down quicker than a factory edge, but it is sure worth it!
> 
> When you have a 15$ Kennemetal insert, it is a nice bonus to get twice the cutting time on it.


 I think he's doing more than just getting twice the cutter time. As I understand it the common criticism of carbide inserts is that they are designed for high speed mass removal of material and don't provide the fine finish or accuracy that can be achieved with HSS at lower speeds and lesser depth of cuts. However this is largely dependant on the nose radius of the carbide insert. By grinding a little off the nose, the nose radius can be reduced to give the carbide insert a different capability.


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## little ol' e (Nov 14, 2022)

VicHobbyGuy said:


> It would be interesting to see a head-to-head test between these KBC Korloy inserts and the same (?) "Korloy" inserts from AliExpress, since there's a 10x difference in price between the two.
> 
> Thinking about the Gotteswinter statement about (modified) carbide inserts: it has been mentioned before that using the  'for aluminum' carbide inserts can work quite well for small lathe/hobby users. The cost (from AliExpress,not KBC!) is not much, so perhaps worth an experiment.


Why the 10x price difference...
Since I never purchased anything from Aliexpress in the past, Let me see if I can explain. Some if not many here probably already know but here goes.....,

Carbide is about 80% cobalt and 20% tungsten across all the competitive tooling companies. Sandvik, Iscar, Die-jet, Mitsubishi, Ingersol and even Kennametal has become very good over the past several years on the milling side of things.

I doubt you will see those percentages in anything Aliexpress has to offer on the cheap side. I could be wrong, but, I have tried many different grade inserts and coatings over the years. I learned to stay away from many.. Seco is another under the umbrella of on the cheap side along side Korloy, Kyocera and several others which I won't comment on...

On a side note,
Do yourself 1 favor, Don't try to re-sharpen a " Carbide Insert " for more life after the coating has worn off and the carbide is clearly full of wear lines and worn... If you know why I say that... That's great, because you already know.

Good luck to all here in the forum, have fun, enjoy the journey with your machines and try to keep an open mind when it comes to tooling, inserts and coatings. @ Degen!

Over and out


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## Susquatch (Nov 14, 2022)

Canadium said:


> As I understand it the common criticism of carbide inserts is that they are designed for high speed mass removal of material and don't provide the fine finish or accuracy that can be achieved with HSS at lower speeds and lesser depth of cuts. However this is largely dependant on the nose radius of the carbide insert. By grinding a little off the nose, the nose radius can be reduced to give the carbide insert a different capability.



That's a valid criticism by many. And I agree with you about that debate. 

My own criticisms are a bit different. As you read my "opinions", keep in mind that I have lots of Carbide tooling and I generally like it. However, 

1. Carbide inserts are expensive. No way around that. It seems that the better they are the more they cost. They cost a lot. Even the cheap ones. 

2. It seems to me in my uses that they break too easily. You cannot sharpen an insert that is missing its whole nose. 

3. They generally require too high a speed for my liking. I don't like high speed except for roughing and I generally do rough with Carbide. 

4. I am a low volume hobbiest/farmer. I don't give a rats butt about volume or production or the value of time. I'm gunna take my time enjoying the task and whether it's carbide or HSS doesn't matter one iota to me. 

5. I feel like you need lots of them both in terms of volume, different styles, and different materials, and different profiles. The complexity and variety is ridiculous. Plus you need a half dozen holders. 

6. For many of my convenience needs, I can get hss inserts. I've never broken one of those yet. 

7. Can't do profiles with inserts unless you have CNC. Must use HSS to grind profiles. 

8. My memory sucks. I can't remember all that insert  terminology. Nothing to remember with HSS. 

9. Somethings just don't work with Carbide Inserts and if they do, I don't know how. Eg Shear tools, tight chamfers, trepanning, tiny boring bars......

10. Lead time - when I have a repair to do, I cannot be waiting for a Carbide Order to arrive. I grab a chunk of hss, grind what I want, and go! 

OK, my flak jacket is on! Bring on the debate!


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## Degen (Nov 14, 2022)

little ol' e said:


> Why the 10x price difference...
> Since I never purchased anything from Aliexpress in the past, Let me see if I can explain. Some if not many here probably already know but here goes.....,
> 
> Carbide is about 80% cobalt and 20% tungsten across all the competitive tooling companies. Sandvik, Iscar, Die-jet, Mitsubishi, Ingersol and even Kennametal has become very good over the past several years on the milling side of things.
> ...


I understand coatings more than you think.  Use my lathe and mill commercially.  I have had my carbide end mills resharpened.   Some recoat, some don't.

Again understand your metallurgy and chemical compositions before mentioned coatings are the best point blank.

I am working up my skill level to sharpen in house on the HSS and Carbide end mills.  Unfortunately for carbide you need diamond wheels to do anywhere near a good job.

As to sharpening inserts again there are specialised jigs and fixtures (which I have some) to be used but considering the low cost of the insert and time involved I wouldn't unless a specific application requires it.


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## Degen (Nov 14, 2022)

Susquatch said:


> That's a valid criticism by many. And I agree with you about that debate.
> 
> My own criticisms are a bit different. As you read my "opinions", keep in mind that I have lots of Carbide tooling and I generally like it. However,
> 
> ...


If you are you are going to try one for general turning I might suggest  these, I love them since I started using them.


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## Degen (Nov 14, 2022)

Dabbler said:


> His context is that of a commercial user.  Even his home shop is now primarily a job shop, and more than half his income derives from it.  He has gone to part time a Bosh Electronics, where he works.
> 
> For a hobby shop there's nothing like HSS, especially in those sub-1-hp lathes and mills.  Somewhere around 3HP, carbide seems to gain the upper hand.  Even on my 7HP lathe HSS has a role.


I started using brazed Carbide and later Carbide Inserts on my old Logan with a 1/4HP motor.  Loved it.  Still used HSS on special cutters for the reasons @Susquatch lists.

When I did my mill riser on that lathe cutting 4041 it was inserts that got the finish and could do the cut.  All done at slow speeds as this was a 70lbs chuck.


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## Susquatch (Nov 14, 2022)

Degen said:


> you are you are going to try one for general turning I might suggest these, I love them since I started using them.



Couldn't agree more. I like them too. Here are mine.






Note the damage on the small one. But to be fair, it has a lot of miles on it.

Not visible in the photo is the grinding I had to do on the big holder to get decent clearance. The original could not be used for face cuts without turning the tool post.

There are two things I especially like about these inserts.

1. They can be simply turned 15 degrees or so for a whole new edge. One insert lasts forever. That small one is about 5 years old and has never been replaced - just turned it a bit to get a fresh edge. This has a huge affect on ROI.

2. They produce a very good finish even at lower speeds than specified. The only thing more reliable is a HSS Shear Tool.

As I said right off the bat, I am not Anti Carbide. Just not anti HSS Either! I think Gotteswinter is crazy despite @Dabbler's explanation.

I'm glad you posted these. I would highly recommend them for other hobbiests too.


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## Susquatch (Nov 14, 2022)

Having just discussed the advantages of round inserts, I confess that I'm quite surprised that nobody has brought up triangular vs rectangular vs diamond vs Trigon etc. Surely all these shapes have their place..... 

I confess I like Trigon inserts. They have three working points, and are generally great for hogging off metal at high speeds and feeds. 

I'm not fond of triangular inserts. But I can't explain why. I guess I just don't trust the reliefs. 

I am ok with rectangular but don't like having just two edges. Why use rectangular when Trigon will do everything rectangular will do with 50% more edges for the money?

I do not like diamond inserts. In my opinion, long points like that are more suited to HSS. 

Flack Jacket On......


----------



## Canadium (Nov 15, 2022)

Degen said:


> I started using brazed Carbide and later Carbide Inserts on my old Logan with a 1/4HP motor.  Loved it.  Still used HSS on special cutters for the reasons @Susquatch lists.
> 
> When I did my mill riser on that lathe cutting 4041 it was inserts that got the finish and could do the cut.  All done at slow speeds as this was a 70lbs chuck.


What speeds (approximate range) do you typically use when using inserts?


----------



## Degen (Nov 15, 2022)

Canadium said:


> What speeds (approximate range) do you typically use when using inserts?


I find that the speed as a lot more flexible.  I do a trial cut or two and adjust accordingly.  Depth of cut depends on two things HP and lathe (or mill) rigidity.  Again trial cuts give you a feel for your machine.

A starting point is the old recommended standard's generally speaking speed can be increased and depth of cut as well.      Some materials will require slower speeds (hardness) with increased depth.

Again all of these adjustments are to achieve finish, accuracy and tool life.

I do strongly recommend cutting or cooling fluids be used as all of these changes increases heat generated and this should be avoided and this should be avoided at all costs.

An longtime old machinist (master machinist) friend put me on to higher speeds over 20 years ago.  His advice was as fast as you can go and get the results you want, book be damned.  Carbide has changed the tables.


----------



## little ol' e (Nov 15, 2022)

Canadium said:


> What speeds (approximate range) do you typically use when using inserts?


I figure most here are machining more mild steels, so I will start with that.

I generally run most inserts in the 400-1800RPM range on a manual lathe. Simply because we can't feed it consistently like a CNC lathe could, therefore, you generate more heat and wear on the inserts. Having said that, it will work really well with the proper grade inserts for both roughing and finishing.

 You want to keep the heat in the chips... The tool needs to stay as cool as you can keep it ( not hot to the touch, warm is where your tool will be most of the time cutting) as well as the bar stock. Use air or coolant, I prefer air.
Why air manually?  Carbide does not like heat or inconsistencies (chip load-feed) Therefore, carbide inserts want to crack and wear quickly when you apply coolants to them.  If your semi finishing or finishing coolant will be ok since your not generating much heat at that point and your only taking .02 semi and .012-.015 for finishing.

When choosing inserts, you want a decent radius for roughing ( At least .03r on any insert you choose) .  I use triangular inserts 85% of the time I would say.
Now, Shell mill inserts as shown above by @Susquach. They are amazing for ruffing in all types of steels. They will eat  A2, D2, PH4140, P20, H13 , 01... that tool will take it no problem. Nice dish for chip breaking and flat top inserts work really well too in that style of insert. Keep the RPMS around 900 unless you can really feed it. Don't go heavy, just take .03 DOC's and the insets will last.

Lets try machining something in airplane mode here,

We will begin with  a 2" diameter bar of HRS with a stick-out of no more than 6"- no tail stock hole since we will face only.
Lets take DavidR8's tool, inserts and go at it.
 Thanks David, we will pay it forward, I promise!

Since we are starting out with only 1 style insert with a .015r, we need to keep the RPMS up a bit for roughing with it, kinda backwards to what we should do, but, I don't have the keys to David's tool box just yet to see if we could use something else.

 Now because of the .015r, that tells us this is a semi finishing/finishing grade carbide insert (we won't get into the coating this time. Why, because it will heat up so quick the coating will be gone in minutes manually machining). Having said that, we know now, this insert and coating does not like heat at anytime, it will turn its nose up and down with heat until it wears down quickly.  Using air or coolant, those inserts will wear rather quickly. Too much heat then add coolant, they will just crack. Carbide inserts need consistency for the most part. The more expensive inserts can withstand much more abuse in manual machining, they have much better coating and tougher grades of carbide.

Lets start roughing...
We will set the RPMS to 750 for our first pass in the 2" diameter HRS bar stock with a stickout of 6" Take .025 feeding slowly with air ( Coolant up to you I would stick with air until finishing )
The insert will now have some wear due to the radius and coating. It will be black around the nose and all around its face. Nothing we can do about it, keep it for skimming the next 1.
Now since that insert has been " heat cycled " and their are other good corners, lets keep that 1 aside for just skimming HRS and the like going forward.

@DavidR8.. We need the keys to your tool box soon lol...

Lets put another insert in since the scale and first .025 depth was a bugger to get through with that insert.

On a side note, for the hobby guys.
 A nice HSS cutter, nicely ground with relief would have done just a good a job at 80-110 rpm with 2 passes at .015
Unfortunately, for new guys, grinding cutters and adding reliefs is not something you can learn so quickly.
Insert changes are quick and make results instantly. That's the trade off. 


Lets try bumping it up to 1200RPM for semi finishing only taking light passes of .015-.02 max doc with this insert feeding it rather quickly for a nice chip color, Lets take it down to 1.890 leaving us with about .015 give or take.  We will finish the last .015 in 2 passes, I mic and split the difference here.
After semi, pull the insert out, put it aside... This will be your semi finishing insert for some time now (hopefully)
Throw in another insert. Don't turn it, put another 1 in, Keep it for finishing.
Lets go to 1800RPM, for the finishing pass, add coolant or WD-40 or what ever flavor oil you like. Amsoil synthetic works too.
A little bit of emery paper to clean up the insert marks if you left any, although it should be a nice finish since we swapped out inserts.

Final note,
When you buy cheaper inserts etc, try to keep track of the lots numbers, this will help when you find yourself stuck as to why the new box of inserts isn't cutting as well as the last 1's did.

 I have never done a write up like this in my lifetime, so, it certainly isn't perfect, but will get you pretty darn close guys.
Time to make twin paper rocket, my brain hurts now.
Hope this helps a bit!


----------



## Canadium (Nov 15, 2022)

Degen said:


> ...........
> 
> An longtime old machinist (master machinist) friend put me on to higher speeds over 20 years ago.  His advice was as fast as you can go and get the results you want, book be damned.  Carbide has changed the tables.



Typical recommended speeds for carbide inserts I've seen bandied about the net are around 2,000 rpm. Considering my old lathe maxs out at 1200 I'm not sure why I'm even considering trying carbide inserts. If as @Susquatch points out the majority like myself are just hobbyists taking our time with limited resources why am I investing big bucks in a brand name QCTP that requires dozens of expensive tool holders, expensive carbide inserts and is better suited to inserts than HSS!? Why not just stick with the freeby old lantern toolpost which may be best suited to the HSS which my lathe is best suited and designed for? I'm afraid that if I were honest I might admit that it's just because QCTP's and carbide inserts are sexier and nothing else!


----------



## little ol' e (Nov 15, 2022)

Canadium said:


> I'm not sure why I'm even considering trying carbide inserts.


From a hobby standpoint.
The key to carbide inserts is about getting instant results rather than grinding HSS or carbide blanks depending on 1's skill level when it comes to grinding.

HSS and carbide blanks will always have its place in manual lathe machining, regardless.
Milling, not so much...


----------



## little ol' e (Nov 15, 2022)

Degen said:


> If you are you are going to try one for general turning I might suggest  these, I love them since I started using them.
> 
> View attachment 27910



Would you say the chips shown on those cutters above ^^^ were produced with a good speed and feed for that type of insert?


Degen said:


> I understand coatings more than you think.  Use my lathe and mill commercially.  I have had my carbide end mills resharpened.   Some recoat, some don't.
> 
> Again understand your metallurgy and chemical compositions before mentioned coatings are the best point blank.
> 
> ...



I understand your experience. You KISS approach is obviously working for you looking at the chips that came off the inserts your learning to love .
 Give em' a Kiss point blank.


----------



## Degen (Nov 15, 2022)

little ol' e said:


> Would you say the chips shown on those cutters above ^^^ were produced with a good speed and feed for that type of insert?
> 
> 
> I understand your experience. You KISS approach is obviously working for you looking at the chips that came off the inserts your learning to love .
> Give em' a Kiss point blank.


Actually the chips on the larger one are from Chinese mystery casting, hard, but powders when you cut it.

The other is scarf from mill running hard fast cuts.

Its not about KISS but biggest bang for the buck.


----------



## thestelster (Nov 15, 2022)

Canadium said:


> Typical recommended speeds for carbide inserts I've seen bandied about the net are around 2,000 rpm. Considering my old lathe maxs out at 1200 I'm not sure why I'm even considering trying carbide inserts. If as @Susquatch points out the majority like myself are just hobbyists taking our time with limited resources why am I investing big bucks in a brand name QCTP that requires dozens of expensive tool holders, expensive carbide inserts and is better suited to inserts than HSS!? Why not just stick with the freeby old lantern toolpost which may be best suited to the HSS which my lathe is best suited and designed for? I'm afraid that if I were honest I might admit that it's just because QCTP's and carbide inserts are sexier and nothing else!


Well, 2000rpm might be suggested for some materials and certain diameter work.  My lathes max speed is 1000rpm, and I use carbide inserts almost exclusively, but I do have HSS bits for certain applications or scenarios.  I think having both systems in your arsenal is advantageous.  But there are certain situations where HSS will not work, ie turning hardened parts.  Or inefficient  ie, turning a large diameter part, where the suggested speed would be so low that you risk falling asleep.  I will extend an invitation to you or anyone for that matter, to come over to my shop, and we can try several cutters, and you can make an honest opinion.  I know you're in Hamilton, but if you come up to the Keswick area feel free to drop by.


----------



## Degen (Nov 15, 2022)

Canadium said:


> Typical recommended speeds for carbide inserts I've seen bandied about the net are around 2,000 rpm. Considering my old lathe maxs out at 1200 I'm not sure why I'm even considering trying carbide inserts. If as @Susquatch points out the majority like myself are just hobbyists taking our time with limited resources why am I investing big bucks in a brand name QCTP that requires dozens of expensive tool holders, expensive carbide inserts and is better suited to inserts than HSS!? Why not just stick with the freeby old lantern toolpost which may be best suited to the HSS which my lathe is best suited and designed for? I'm afraid that if I were honest I might admit that it's just because QCTP's and carbide inserts are sexier and nothing else!


Start with one insert holder and see how you like it, forget the QCTP, make yourself a 4 position holder, no you don't need a mill, this is the first thing I made for my Logan with the Logan.  Teaches you a lot about lathe work and set up.

No need to dive in with Big Bucks, go slow and easy.

As to speed, use what you have play a little to maximize performance this is what makes you better then the rest.

One other thing learning how to hand grind is a skill you should learn even if you abandon it later, again teaches you a lot about metals/tooling and edges.


----------



## little ol' e (Nov 15, 2022)

Degen said:


> Actually the chips on the larger one are from Chinese mystery casting, hard, but powders when you cut it.



Ok... I will give you that 1. Hard Chinese mystery casting that turns into powder while machining it.


Degen said:


> The other is scarf from mill running hard fast cuts.


I think they call it swarf/turnings or chips but it any case,
What were your speeds and feeds during your hard fast cuts producing those chips on tool #2 ? Also in what material... to help other members understand what the chip loads and chips will look like if they were to try this.
Thanks


----------



## David_R8 (Nov 15, 2022)

Degen said:


> One other thing learning how to hand grind is a skill you should learn even if you abandon it later, again teaches you a lot about metals/tooling and edges.


I heartily agree; there is almost nothing so satisfying as watching a thick peel of metal coming off a sharp HSS bit.


----------



## PeterT (Nov 15, 2022)

@Degen are you sure these inserts/toolholders are meant for general turning? The pocket (support) is aligned to suggest plunging like making a groove or fillet operation. I've also seen them in lathes used for profiling / blending, but usually CNC. Or facing mill heads in a mill setup.

I have a 6mm insert / toolholder like yours. On my 303SS valves I tried turning the stems with the same tool since that also becomes the blend radius. It was not pretty. Significantly more load imparted to the part vs a smaller radius conventional cutter for the same DOC. I've tried the same cutter in other materials for finishing, aluminum & steel. Performs about as I expected. There was no advantage over conventional lathe inserts with say 1.5mm nose radius. I would not run a HSS tool of that equivalent 6mm radius (at least not on my 14x40) because the tool contact line is significantly longer than a conventional cutters even though is suppose the round insert is stronger. Hobby machines generally have less rigidity, lower HP, looser slide tolerances - usually a recipe for chatter.


----------



## little ol' e (Nov 15, 2022)

David_R8 said:


> I heartily agree; there is almost nothing so satisfying as watching a thick peel of metal coming off a sharp HSS bit.


X2, then you have time to answer the phone and do a quick quote while its making a pass.


----------



## Degen (Nov 15, 2022)

PeterT said:


> @Degen are you sure these inserts/toolholders are meant for general turning? The pocket (support) is aligned to suggest plunging like making a groove or fillet operation. I've also seen them in lathes used for profiling / blending, but usually CNC. Or facing mill heads in a mill setup.
> 
> I have a 6mm insert / toolholder like yours. On my 303SS valves I tried turning the stems with the same tool since that also becomes the blend radius. It was not pretty. Significantly more load imparted to the part vs a smaller radius conventional cutter for the same DOC. I've tried the same cutter in other materials for finishing, aluminum & steel. Performs about as I expected. There was no advantage over conventional lathe inserts with say 1.5mm nose radius. I would not run a HSS tool of that equivalent 6mm radius (at least not on my 14x40) because the tool contact line is significantly longer than a conventional cutters even though is suppose the round insert is stronger. Hobby machines generally have less rigidity, lower HP, looser slide tolerances - usually a recipe for chatter.
> 
> View attachment 27924


I have the others set ups as well, for heavy stock removal I use the larger of the 2 generally, the smaller one of mine is straight like @Susquatch and cuts left/right faces and in both directions very similar to a well ground HSS bit while allowing faster feeds (radius nose) maintaining a smooth finish compared to pointed bit.  It has become my do all cutter on the lathe as it is one setup multiple choices for cuts and it leaves a nice stress free radius in the inside corners.


----------



## Degen (Nov 15, 2022)

David_R8 said:


> I heartily agree; there is almost nothing so satisfying as watching a thick peel of metal coming off a sharp HSS bit.


Same for carbide, just get to do mire cuts before sharpening/changing.


----------



## Susquatch (Nov 15, 2022)

Canadium said:


> Typical recommended speeds for carbide inserts I've seen bandied about the net are around 2,000 rpm. Considering my old lathe maxs out at 1200 I'm not sure why I'm even considering trying carbide inserts. If as @Susquatch points out the majority like myself are just hobbyists taking our time with limited resources why am I investing big bucks in a brand name QCTP that requires dozens of expensive tool holders, expensive carbide inserts and is better suited to inserts than HSS!? Why not just stick with the freeby old lantern toolpost which may be best suited to the HSS which my lathe is best suited and designed for?



The following is not a professional opinion. Just my own observations. I don't know where you are seeing typical speeds of 2000 rpm. In my experience, the ideal speed is usually expressed as surface feet per minute. The speed is only relative to the diameter. The bigger the diameter the slower the required rpm. Small diameters dictate faster rpm. FWIW, my lathe won't do 2000 rpm. 1400 is the fastest it goes. My mill will do 2720 from the factory and 4500 with my VFD (I'll never run that fast though). 

For HSS, I have a nice Laminated wall chart that shows speed vs diameter vs materials as curves. I keep it on the wall behind my lathe. I don't really know if it's any good, but it works for me for HSS.






Diameter is on the left vertical axis, rpm across the top, and the colours are for material. I don't get religious about it though. I just pick a median number and then play with it up or down till I'm satisfied with the results.

On the other hand, most of the higher quality inserts come with recommendations for surface feet per minute (sfm) and feed rate. In these cases a calculation is required. I think the guys who do this stuff for a living just seem to know what speeds and feeds to use just looking at it. They have probably done the calcs so many times it became un-necessary to do it because they already knew what the answer would be. For stuff I do often, that's already the case even for a hobbiest like me. In fact, since I don't really have any really high quality inserts or holders yet, I have no factory recommendations to go by. So I have developed a sort of gut feeling about what works based on looking at the insert, the nose radius, and the edge sharpness. Those round inserts are pretty forgiving because they are sharp and have a huge nose radius. For the trigons I use for hogging, I crank everything up a few notches. Not nearly like @thestelster though. For me, even 40 thou is scary. I'm too old and too slow to do what the pros do. I get the job done though and in my world, that's all that matters. 




Canadium said:


> I'm afraid that if I were honest I might admit that it's just because QCTP's and carbide inserts are sexier and nothing else!



I confess that I laughed so hard at this that I had tears running down my pantlegs! Truer words have never been said. 

How many new lathe owners have not done exactly that? I know I did! It was one of my biggest mistakes. I would have been waaaay better off taking my time to buy what I needed and could use instead of the crap that seduced me. 

I think BusyBee, and Grizzly, and King and and and, are all out there seducing us to buy these mostly useless kits. 

That said, my newest lathe came with a BXA Quick Change Tool Post, so I didn't get sucked into buying that. And I also confess I like the QCTP. If I were talking to a new user who was considering a QCTP, I'd prolly recommend they go for it. And then buy more tool holders as needed. They come up on sale frequently and do make life easier for both HSS and carbide. 

In my opinion and experience, the biggest difference between a QCTP vs a lantern post is stiffness. I think those lantern tool posts were horrible for stiffness. I lived with one for 30 years. I do not miss it. That doesn't mean I didn't do good work with it. I did! But I was constantly fighting chatter, poor finish, and decent cut depth. Parting was done with a hacksaw. 

On the other hand I think those four sided tool posts are ok. If that is what had come with my newer lathe I might still be using it. The fact is that "quick change" is about convenience not function. As @Dabbler has said, an argument can be made that makes a 4 sided tool post faster than a QCTP in some circumstances. 

So ya, I'd recommend a 4 sided tool post or a QCTP, but I don't recommend those economy tool kits. My own quest is to find the right tools to minimize my spending and provide the most flexibility and function.


----------



## Susquatch (Nov 15, 2022)

PeterT said:


> are you sure these inserts/toolholders are meant for general turning? The pocket (support) is aligned to suggest plunging like making a groove or fillet operation. I've also seen them in lathes used for profiling / blending, but usually CNC. Or facing mill heads in a mill setup.
> 
> I have a 6mm insert / toolholder like yours. On my 303SS valves I tried turning the stems with the same tool since that also becomes the blend radius. It was not pretty. Significantly more load imparted to the part vs a smaller radius conventional cutter for the same DOC. I've tried the same cutter in other materials for finishing, aluminum & steel. Performs about as I expected. There was no advantage over conventional lathe inserts with say 1.5mm nose radius.



Peter - your question was not directed to me. But the picture you linked was mine not Degens.

I don't usually use those tools for plunge cutting but I have done it. I also don't use them for general cutting like degen said he did. Mine are mostly reserved for those times when I need a better finish. They do a great job of that for me. I don't know why your experience isn't the same. Perhaps you are taking too big a cut? I find the round bits cut almost as good as a shear tool. On shallow cuts, they almost seem to peel off a very thin piece of foil. The resulting finish is usually very good. I also run them a lot slower than one might guess for a carbide tool. That's what trial and error has done for me. That works for almost any material from stainless to 4140 to mild steel to brass to aluminium.

You are right though, they also work well if you need to contour a surface manually.

At any rate, unlike Degen, I don't consider them a general purpose insert. I will almost always reach for HSS or a Trigon insert for general purpose work.


----------



## thestelster (Nov 15, 2022)

Susquatch said:


> For HSS, I have a nice Laminated wall chart that shows speed vs diameter vs materials as curves. I keep it on the wall behind my lathe. I don't really know if it's any good, but it works for me for HSS.


You really have to download the free FSWizard app.  It will give you speeds and feeds for most machining operations, many types of materials and hardness you're working on, cutter material, coatings on the cutter, depth of cut, corner radius, tool stick out, and overrides.  By overrides, I mean for instance, that the app might suggest using a particular speed or feed, and it tells you that it will require 5Hp for that cut, but you only have a 2Hp motor.  Just go into the override to reduce the hp rating to what your motor is, and it adjusts the speed or feed.  Or also to override for the maximum speed of your lathe or milling machine.  I use this app almost every time I machine something (especially if I'm using HSS cutters or endmills or drill bits, to adjust for speed, otherwise they'll burn up.  Carbide is more forgiving in the speed variance.)  And you don't have to plug in all the variables, just the material you're machining, the cutter material, and the diameter, and you will have some good start values to use.


----------



## Susquatch (Nov 15, 2022)

For those who are wondering, these are my two hogging tools for removing a lot of material fast - though not as fast as @thestelster ...... That man drives an F35 to work every day...... I have a Clydesdale.






I might help to understand that my main source of stock is old bolts - of all sizes and strength from little screws to massive 2" bolts with 6 pitch threads. So hogging is often standard procedure before I can get to the required work.


----------



## Susquatch (Nov 15, 2022)

thestelster said:


> You really have to download the free FSWizard app.  It will give you speeds and feeds for most machining operations, many types of materials and hardness you're working on, cutter material, coatings on the cutter, depth of cut, corner radius, tool stick out, and overrides.  By overrides, I mean for instance, that the app might suggest using a particular speed or feed, and it tells you that it will require 5Hp for that cut, but you only have a 2Hp motor.  Just go into the override to reduce the hp rating to what your motor is, and it adjusts the speed or feed.  Or also to override for the maximum speed of your lathe or milling machine.  I use this app almost every time I machine something (especially if I'm using HSS cutters or endmills or drill bits, to adjust for speed, otherwise they'll burn up.  Carbide is more forgiving in the speed variance.)  And you don't have to plug in all the variables, just the material you're machining, the cutter material, and the diameter, and you will have some good start values to use.



Great tip! I shall do it right now! I like handy apps like that!


----------



## Susquatch (Nov 15, 2022)

thestelster said:


> You really have to download the free FSWizard app.



It's installed. The very first barrier I hit is that it appears to be for milling. I know they can be related but it would be easier if I didn't have to do the conversion. Do you use something similar for your lathe? 

I also noticed a Sandvik app when I was looking.


----------



## Susquatch (Nov 15, 2022)

Susquatch said:


> It's installed. The very first barrier I hit is that it appears to be for milling.



Hmmmmm, going back over this thread, it looks like lots of members are talking mills while others are talking lathes. Might be the cause of some of the confusion.


----------



## thestelster (Nov 15, 2022)

Susquatch said:


> It's installed. The very first barrier I hit is that it appears to be for milling. I know they can be related but it would be easier if I didn't have to do the conversion. Do you use something similar for your lathe?
> 
> I also noticed a Sandvik app when I was looking.


There's a box for "Tool Type", hit it and scroll to what you want to do.


----------



## Susquatch (Nov 15, 2022)

thestelster said:


> There's a box for "Tool Type", hit it and scroll to what you want to do.



And so there is..... 

Too many choices...... This is gunna hurt but prolly worth playing with it after my Clydesdale gets thirsty......


----------



## thestelster (Nov 15, 2022)

Click on the first banner beneath the blue upper section, and chose your material.

The banner below that is the type of operation, milling  turning, drilling, reaming, threading, etc.

The rest are other parameters and overrides.  The recommend starting data is in the upper blue banner.  Make sure that the starting data HP is smaller than your motor.  If not adjust the parameters in the override sliders until it is.


----------



## Dabbler (Nov 15, 2022)

@PeterT Th button inserts in post #122 can be used for hogging on *very* large machines.  For a vid of someone doing this look at recent hydraulic cylinder rebuilds on youtube - Cutting Edge Engineering.

BUT Curtis is using a 15 HP or 20 HP lathe (he has 2) and each lathe weighs more than your shop, and he still gets chatter.

Using button inserts on a 3HP hobby lathe is limited to light cuts unless you are a 'machine abuser'.


----------



## little ol' e (Nov 15, 2022)

@PeterT as well,

I use the button style inserts on the CNC lathe for the most part.
They do hog and produce nice surface finishes as Dabbler mentioned above.
They only time I would use them on a manual lathe would be if I have a quick 1 off shaft or bushing that needed grease grooves.
The cutter bodies come in another style for internal grease grooves as well.
This is what I use that style of holder and insert for on CNC, not so much for manual machining.
It takes a good amount of horsepower and torque to push this style cutter.  That's why they don't work well for the hobby guys with smaller lathes with limited torque and horsepower.

  Here are some pics,


----------



## PeterT (Nov 15, 2022)

Susquatch said:


> Peter - your question was not directed to me. But the picture you linked was mine not Degens.
> 
> I don't usually use those tools for plunge cutting but I have done it. I also don't use them for general cutting like degen said he did. Mine are mostly reserved for those times when I need a better finish. They do a great job of that for me. I don't know why your experience isn't the same. Perhaps you are taking too big a cut?



Fair enough. His post showed 2 toolholders with no further elaboration or distinction. The one on right looks like a neutral toolholder which is what I was referring to. I'm suggesting the toolholder pocket orientation & thinner shank under the insert is probably suited to mainly oblique or plunge orientation vs side load. Hogging or even heavy cutting is heavy sideload.

As for your second question, nope, the lightest of cuts. I just don't see the improvement over say a 1.5mm radii conventional insert toolholder. I can take a picture of a half thou shaving coming with a mirror finish using conventional insert but I don't really have a horse in this race. Use whatever gets you the results. 

I'm trying to find some references (from insert manufacturers) that recommend a large radius or circular insert to be preferable for finishing cuts. Seems like what they call finishers come under variants of  their conventional (faceted) inserts, with other geometric features, nose radii, rake, coating... variants. But I haven't looked too deep. Do you have some links? 

Large diameter strikes me as counterintuitive. I mean if 6mm round insert makes a better finish than 1.5mm radii faceted insert, why stop there? Increase the radii to 10mm, 15mm? To me, its because diminishing returns and/or as contact arc increases, other factors enter the picture: rubbing, friction, heat, chatter, smearing... all anti-good finish attributes. The increased arc length is not like a mill cutter where the helix & turn orientation control chip thinning & other attributes. On a lathe, the entire profile is in contact with material. 






						How To Choose The Correct Carbide Inserts - Protool
					

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						Demystifying Insert Nose Radius Selection
					

Even among experienced machinists, choosing the right insert for boring a hole remains a difficult process that is fraught with myth and misconception. However, it is no myth that insert selection can completely save or kill performance on an application.




					www.bigdaishowa.com


----------



## thestelster (Nov 15, 2022)

Some information from the Sandvik catalogue.


----------



## Susquatch (Nov 15, 2022)

PeterT said:


> Fair enough. His post showed 2 toolholders with no further elaboration or distinction. The one on right looks like a neutral toolholder which is what I was referring to. I'm suggesting the toolholder pocket orientation & thinner shank under the insert is probably suited to mainly oblique or plunge orientation vs side load. Hogging or even heavy cutting is heavy sideload.



Just to be clear, I do not (and never did) advocate heavy cuts with these round inserts.



PeterT said:


> As for your second question, nope, the lightest of cuts. I just don't see the improvement over say a 1.5mm radii conventional insert toolholder. I can take a picture of a half thou shaving coming with a mirror finish using conventional insert but I don't really have a horse in this race. Use whatever gets you the results.



I don't think I have any inserts with a nose radius that big (1.5mm). That's a pretty round nose (3mm diameter). I wouldn't be at all surprised to find that such a nose yields an excellent surface. Perhaps better than the round insert.



PeterT said:


> I'm trying to find some references (from insert manufacturers) that recommend a large radius or circular insert to be preferable for finishing cuts. Seems like what they call finishers come under variants of their conventional (faceted) inserts, with other geometric features, nose radii, rake, coating... variants. But I haven't looked too deep. Do you have some links?



I never said that manufacturers recommend this. It's just what I found from my own experimenting. Also, it's worth noting that ALL MY INSERTS ARE CHEAP CHINESE INSERTS. I don't have any really good ones yet. I don't have any good holders either. That's the whole point of my search for recommendations from other members. I have no stomach for buying and testing dozens of very expensive inserts and tool holders only to find that they don't work because because because. I think there are a lot of other hobby machinists who could benefit from the same advice. 



PeterT said:


> Large diameter strikes me as counterintuitive. I mean if 6mm round insert makes a better finish than 1.5mm radii faceted insert, why stop there? Increase the radii to 10mm, 15mm? To me, its because diminishing returns and/or as contact arc increases, other factors enter the picture: rubbing, friction, heat, chatter, smearing... all anti-good finish attributes. The increased arc length is not like a mill cutter where the helix & turn orientation control chip thinning & other attributes. On a lathe, the entire profile is in contact with material



Well, it's not that I disagree. However, one could make the opposite extension of logic. I mean if 1.5 mm makes a better finish than 6mm, why stop there? Why not 1mm or 0.5mm? We all know that doesn't play out very well.

I don't think either logical direction holds water. Instead I expect that there is a sweet spot and furthermore that the sweet spot depends on a whole host of factors. For example, the one photo you attached shows a pretty aggressive depth of cut.






When I use round inserts for finishing purposes, my depth of cut might be 10 to 5 thou or even less. So the cut does not involve the entire radius - only a very small arc of it.

For the best finishes, I don't use the round inserts either, I use a hss shear tool. And of course, it all depends on what you are after.

Anyway, this is turning into a bit of a defense of my own use of round inserts and that isn't the purpose of this particular thread (I am the OP). The purpose is to ask others what they use and why.

I would like to get some good input on what you use and how it works out for you.

Do you use the same insert with many holders to achieve versatility?

Do you maintain a stock of a particular insert with different nose profiles? Different coatings?

Etc etc.


----------



## Degen (Nov 15, 2022)

www.shars.com  download their catalog goto page 107 to 140  they have a good selection and read.  Better than KBC unfortunately.


----------



## PeterT (Nov 15, 2022)

Susquatch said:


> When I use round inserts for finishing purposes, my depth of cut might be 10 to 5 thou or even less. So the cut does not involve the entire radius - only a very small arc of it.
> For the best finishes, I don't use the round inserts either, I use a hss shear tool. And of course, it all depends on what you are after.



Maybe some of the folks who do his for a living can comment if I'm interpreting the insert manufacturer recommended operating envelope properly (the little chart that typically accompanies the insert description), or if I'm out to lunch. I do accept that this is 'recommended' & likely focused on their customer base (predominantly CNC machines). But OTOH the world doesn't explode if you operate slightly outside the range on a hobby lathe. But just in general terms, does this logic go around?

if I take @thestelster Sandvik catalog showing the 2 round inserts, a couple observations
- they appear to be for quite different purposes despite both being 'round'. I marked up the operating range from RNMG & superimposed onto RCMX. RCMX appears to be a substantially more aggressive operating envelope, both in terms of DOC & feed
- the RNMG envelope base (the minimum DOC) is 0.047" That is a healthy cut
- for visual reference I drew a 0.002" DOC (dash pink line) just to provide a common reference. No logic to selecting that particular value other than many of us can relate to that as being somewhat like a 'finishing cut' in our hobby domain, creeping up to a target dimension finish on something important. Notice how pink line is substantially below the envelope of both RNMG & RCMX range, but its way below RCMX

I grabbed Dorian catalog randomly, link below. They have lots of finishing inserts listed, majority of which are faceted (non-round).
- Screen grab shows their operating range, a bit different format but I think consistent units? I made a boundary box (blue) around the finisher

Excel plot shows the 3 inserts superimposed to each other. I didn't capture the RCMX curve envelope quite correctly, but you get the general idea.
- look at the 0.002" DOC pink line relative to the faceted insert. It seems it is designed for this type of skimming

@Susquatch using your example 0.005-0.010" DOC range, still a distance below the minimum recommended RNMG. But lets assume the finish is spectacular, that DOC value presents a more challenging operating strategy. Because if you want to hit finish AND dimension simultaneously, say a shaft to fit a bearing, you step in say 0.010" increments. If you are off 10%, that's 0.001". If you select the UEU finisher, the increment step cane be is 0.002", 10% deviation is 0.0002"

If I'm misunderstanding interpretation of the plots please let me know. Pretty sure we have chatted this topic in the past, because my next line is.... what would be REALLY useful is to see HSS on the same format plot. Ever seen references along those lines?




			https://www.doriantool.com/wp-content/uploads/dorian_tool_TurningTools_CarbideInserts_.pdf


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## Degen (Nov 15, 2022)

I'm going to mess things up a little and back track to interrupted cutting with....






Let the fur fly.


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## PeterT (Nov 15, 2022)

thestelster said:


> FSWizard app



@thestelster  do you need to create an account to run? When you say app do you mean phone or PC or does it make a difference?
Looks like it has some useful calculation metrics, but it doesn't seem to be responding to new inputs. I was hoping to evaluate HP as a function of nose radius for HSS.


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## Susquatch (Nov 15, 2022)

PeterT said:


> Susquatch using your example 0.005-0.010" DOC range, still a distance below the minimum recommended RNMG. But lets assume the finish is spectacular, that DOC value presents a more challenging operating strategy. Because if you want to hit finish AND dimension simultaneously, say a shaft to fit a bearing, you step in say 0.010" increments. If you are off 10%, that's 0.001". If you select the UEU finisher, the increment step cane be is 0.002", 10% deviation is 0.0002"
> 
> If I'm misunderstanding interpretation of the plots please let me know. Pretty sure we have chatted this topic in the past, because my next line is.... what would be REALLY useful is to see HSS on the same format plot. Ever seen references along those lines?



I can't really comment much on what you have posted Peter. 

I do agree with your comments about creeping up on dimensions. I don't have the knowledge or skills or confidence to do that with a carbide insert of any type. I would only ever use HSS for that. Your 10% error window is a good way to look at it. I can't begin to try the approach I've read others write about where they take 10 or 20 off to hit a final number. Doesn't work for me - I creep up on it. Not always successful even at that. My use of the round inserts is strictly finish and stress relief. 

046 minimum cut? Ya, that is F23 territory. 

Thanks for posting the Dorian link. I added it to the insert reference thread. 

Also not going to comment on the Dorian data or your interpretation of it. Maybe some day after I get some inserts and holders of that quality. 

I don't think I've ever seen anything like that for HSS. I'll certainly keep my eyes open.


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## Susquatch (Nov 15, 2022)

Degen said:


> I'm going to mess things up a little and back track to interrupted cutting with....
> 
> 
> 
> ...



Not a very good example of interrupted cuts. They still start gradual and don't hit a sharp edge or corner. In other words, the shock load is very low.


----------



## thestelster (Nov 15, 2022)

PeterT said:


> Maybe some of the folks who do his for a living can comment if I'm interpreting the insert manufacturer recommended operating envelope properly (the little chart that typically accompanies the insert description), or if I'm out to lunch. I do accept that this is 'recommended' & likely focused on their customer base (predominantly CNC machines). But OTOH the world doesn't explode if you operate slightly outside the range on a hobby lathe. But just in general terms, does this logic go around?
> 
> if I take @thestelster Sandvik catalog showing the 2 round inserts, a couple observations
> - they appear to be for quite different purposes despite both being 'round'. I marked up the operating range from RNMG & superimposed onto RCMX. RCMX appears to be a substantially more aggressive operating envelope, both in terms of DOC & feed
> ...


Hi Peter, with those round inserts by Sandvik, the RCMX info is based on an insert size of 20mm (0.787"), while the other one the data is for a 1/2" insert.  That's why the max depth of cut is so different between the two.  So you can't compare the two.  Plus the RCMX has 2x the edge width (0.008") compared to the other.  The wider the edge, the stronger, designed for roughing.


----------



## thestelster (Nov 15, 2022)

PeterT said:


> @thestelster  do you need to create an account to run? When you say app do you mean phone or PC or does it make a difference?
> Looks like it has some useful calculation metrics, but it doesn't seem to be responding to new inputs. I was hoping to evaluate HP as a function of nose radius for HSS.


Hi Peter, yes you're right, it doesn't change the results for different nose radii.  Perhaps on the pay version it works?    But most everything else it does.  Once you change an input, click somewhere else on the screen and it will change to the correct values.

I have the app on my Android phone.


----------



## johnnielsen (Nov 15, 2022)

To answer Susquatch's original query, I have used predominantly dnmg 432 to 435
coated inserts, mostly Sandvik, since 1979. A right hand tool holder with 2 degrees of lead allow me to turn, face and plunge which is a real timesaver when you want to make chips.


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## PeterT (Nov 15, 2022)

Susquatch said:


> Thanks for posting the Dorian link. I added it to the insert reference thread.
> Also not going to comment on the Dorian data or your interpretation of it. Maybe some day after I get some inserts and holders of that quality.



Just to clarify, Dorian is above my pay grade. I'm just a catalog grazer. I have a few euro toolholders purchased from KBC a while back. Decent quality (for me) & it was still less than the big boy brands. I also sampled a few inserts from the likes of KBC & Travers. Once I started buying from Ebay sellers (sometimes Ali too but I'm more picky) I was hard pressed to tell the difference to justify the cost, so that is what I've stuck with. Now is my Ebay Korloy a real Korloy? I don't know. But my experience thus far is I cant wear them out fast enough in my lifetime to fret about it when a box of 10 is $25 or whatever. Most chipped edges are self inflicted, but I also don't do much heavy cutting or hard material turning. The biggest performance/finish differences have been the type of insert itself. The Ebay suppliers take the $ sting out of trying others. Recently I tried some optimized for stainless & they did seem better than the general steel ones I used prior. The Ebay/Ali toolholders seem to be semi hardened 4140. Nothing special but they seem to do the job.

Another good technical reference is Korloy. I've had to cross reference certain PN's when I see them on Ebay type seller sites. Korloy publish a few different documents, some are higher level summary (digest) or you can geek out with the technical catalog. 





						Catalogue | Download | KORLOY
					

Catalogue | Download | KORLOY




					www.korloy.com


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## Susquatch (Nov 16, 2022)

thestelster said:


> Hi Peter, with those round inserts by Sandvik, the RCMX info is based on an insert size of 20mm (0.787"), while the other one the data is for a 1/2" insert.



Holy Crap! A 3/4" round insert! Ya, that's F35 territory! Even 1/2" is big for me. My big one is maybe 3/8 and my small one is maybe 1/4 (but I didn't measure them). Regardless, the bigger they get, I think the harder it becomes to get a good finish. I might as well be trying to use a huge parting tool. That's prolly also why my small tool is so well used compared to my big one. Again kinda the opposite of your bigger ought to be better scenario @PeterT. Or to put it a different way, maybe smaller is closer to a large radius tip on a rectangular insert.


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## Susquatch (Nov 16, 2022)

PeterT said:


> Just to clarify, Dorian is above my pay grade. I'm just a catalog grazer. I have a few euro toolholders purchased from KBC a while back. Decent quality (for me) & it was still less than the big boy brands. I also sampled a few inserts from the likes of KBC & Travers. Once I started buying from Ebay sellers (sometimes Ali too but I'm more picky) I was hard pressed to tell the difference to justify the cost, so that is what I've stuck with. Now is my Ebay Korloy a real Korloy? I don't know. But my experience thus far is I cant wear them out fast enough in my lifetime to fret about it when a box of 10 is $25 or whatever. Most chipped edges are self inflicted, but I also don't do much heavy cutting or hard material turning. The biggest performance/finish differences have been the type of insert itself. The Ebay suppliers take the $ sting out of trying others. Recently I tried some optimized for stainless & they did seem better than the general steel ones I used prior. The Ebay/Ali toolholders seem to be semi hardened 4140. Nothing special but they seem to do the job.



This is good stuff Peter. I was under the impression that you were a fan of the big dollar tools since that's mostly what you quote. But you are still a significant step beyond me. 

With a few exceptions, all my stuff is discount tooling and my inserts are either Ali or BusyBee or Accusize. I bought a few parting inserts from KBC and I love them. They actually work! That's a huge step forward for me. 

In fact, that's sorta what started me on this journey. If KBC inserts are so much better, then maybe I should try a few other types...... I wonder what the guys who do this all the time use.......


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## little ol' e (Nov 16, 2022)

Susquatch said:


> In fact, that's sorta what started me on this journey. If KBC inserts are so much better, then maybe I should try a few other types...... I wonder what the guys who do this all the time use.......


I am referencing Susquach's post here, but throwing this out to all interested on the board here.

I began machining in 1982, manual mills, lathes, grinders, radial drills in a Tool & Die shop. Been machining ever since full time and continue to do so.

IMO, their is no difference between CNC lathe machining vs manual Lathe machining. The only difference with a CNC lathe is higher speeds/feeds- contour machining, quick thread turning etc. Plus, given the added HP/TQ and mass weight of the machines as most here know.
The plus side of CNC, begins with finishing IMO.
 Roughing is just roughing across the board. ( as long as you can keep heat expansion down you can hit stock to leave tolerances for semi finishing. It is also possible to skip the semi finishing and go rite into finishing with the indexable tooling on the market these days.
For example,
You can rough to .012 these days, then get into finishing.  ( As long as you use the proper insert grade and coating for the material your machining, with optimum speeds and feeds to limit heat expansion and wear of the inserts)

Finishing at higher speeds and feeds in CNC gives you good control, accuracy and surface finishes.
This step can often be very difficult for many to achieve on a manual lathe when machining tougher materials unless using indexable with coating/s.
Not to say it cannot be achieved manually, you just need to throw better quality inserts at it if you want to finish it within a reasonable time frame without having to constantly grind HSS and  "uncoated carbide blanks". ( We know what grinding uncoated carbide will do over time to us without a mask, now add coatings...)
If you have good grinding experience with HSS, uncoated carbide, and time, then you can always get by with cheaper insert options available for something you want to machine quickly. ( KORLOY for example)

Let me see if my old brain can explain what Carbide inserts are all about while trying to keep it simplified.

Think about it as if you only have 3 grades of carbide inserts, with several different coatings to choose from ( Just keeping it simple )

1) General purpose insert with a few layers of coating-  They can withstand some heat, shock, a little chatter yet still hold an edge unless rigidity becomes an issue through too much chatter.  These inserts are decent for softer materials but as you get up into 4140, H13, P20 ( 38-45rc ranges) these inserts will wear very quickly.

2) Mid-grade inserts have addition layers of coatings to withstand heat for the most part. Therefore keeping the wear down before getting to the carbide.
These inserts can handle 4140, PH4140 into A2 D2 keeping your speeds and feeds in check for the material hardness your machining.
They can handle some chatter, shock and interrupted cuts but... Be careful,,,

 Once the coating comes off, your on borrowed time and the next pass you will be changing inserts. ( Perhaps Degen or others could help explain coatings more in depth if he gets time here, since I'm not really up to speed with them. )

3) Hard grade inserts have the ability to machine harder materials with higher speeds and feeds. However, they need a constant feed, speed and chip load to survive.
They cannot take much shock, chatter or anything interrupting the cut , but, the insert can withstand more heat.  You need to have a good uniform stock for this insert to perform its best. They have multiple layers of coating to make this happen.

- Button inserts- They are wicked, for ruffing and finishing but they need material to bite into or your just grinding with them slowly removing the coating.
Anything under .025 DOC, I find they just wear too quickly in a chip breaker form ( Dished insert)  The flat top inserts have multiple coating layers, these are for lighter cuts but still like at least .015 material to bite into or they just ware away like grinding.

Any insert with a radius of .03 and up generally used for roughing and semi finishing only. They need to bite as well.
The same 3 simple principles apply when choosing a insert. ( Increased radius for ruffing at lower RPMS with coating that will withstand what you are machining.

Finishing inserts have smaller rads since you are running at higher speeds and feeds, be it manual lathe machining or CNC.
It all about what your manual lathe can handle and how consistent you can keep your DOC's at and cross feeds with the RPM you choose.

As I mentioned in the past, write ups are difficult for me lol.
I got 2 credits in grade 9 highschool so that should explain things haha.
I was a trade school guy when I left highschool at age 16

Hopefully what I did type helps to it simple enough for all.


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## thestelster (Nov 16, 2022)

Here is a link to the Sandvik Turning Handbook: 

https://coromantstrgprod.blob.core....=t+nlI3N0olYsL5dm9B6aRAK1xQ4IJyMVUl6z/8pLio0=


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## little ol' e (Nov 16, 2022)

Without focusing on a brand of insert here....
These are my go to inserts daily for turning. Both CNC and manually.
They are mid grade with several layers of coating.
Keep in mind, the coatings are what makes these inserts last, not the carbide under them.
Once the coating has worn, I turn them. If not, I would be generating too much heat and friction, at that point... tolerances are difficult to hold at that point as well.
You can see the wear on the triangular insert coating. I could run them further but I know that edge won't hold up much longer now that the coatings have worn off.
I then use them inserts on the manual lathe since they are no longer useful on the CNC lathe. Unless I'm standing at the CNC machine waiting for them to go, again I'm on borrowed time with then on the CNC lathe.

Triangular for roughing, diamond for finishing... that's it.
I'll add a threading insert as well.


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## little ol' e (Nov 16, 2022)

Different coatings shown below-  Optimal for CNC turning, but can get expensive...
That is why I suggested Tialn coatings for the manual side of things. Be it lathe or mill.
 No point in wasting your money on the high end coated stuff unless you are a seasoned machinist IMHO.

 I looked on Aliexpress this morning...   seen inserts with Tialn coatings.
For manual machining, I would start their since you guys are familiar with purchasing from them. I would not pay more for them from KBC, Korloy anyway.  That is just my opinion thou since I have not tried any of them out.

Hopefully Degen can comment more about these coatings since he has the knowledge with these types of coatings and substrates, including TIALN coatings that I suggested for manual turning.


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## Susquatch (Nov 16, 2022)

johnnielsen said:


> To answer Susquatch's original query, I have used predominantly dnmg 432 to 435
> coated inserts, mostly Sandvik, since 1979. A right hand tool holder with 2 degrees of lead allow me to turn, face and plunge which is a real timesaver when you want to make chips.



Perfect John! Exactly what I have been after! Especially the versatility of turn, face, and plunge. I've liked off shore Trigons for turning and facing, but they won't plunge - at least not on my machine. If I could find a good tool and inserts that would be versatile, last long enough to be cost effective, forgiving of my many mistakes, and leave a decent finish behind that isn't embarrassing, I'd be a very happy camper. In fact, I'd even settle for a bad finish that needs cleaning up with another tool. 

I don't suppose you have a recommended tool part number for them? Or do you think that is important?


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## Dabbler (Nov 16, 2022)

I'd like to add a comment, certainly out of order.

I've used the cheapest of the cheap, mid-range and premium inserts over that last 40 years.  Yes even before ISO designations for inserts were commonly available sizes.

Here's my take for a hobby guy, and until tha last 14 years using a 1.5 HP lathe and 1 HP mill.

If you use the cheap ones carefully, they will get you by.  They are better than HSS in tough stuff like shafting (4330 in my case), but they don't last long and won't survive interrupted cuts or tough situations.

During all this time I also was using Kinnemetal tooling (holder and inserts) for a single tool, a triangle tool in my 12X37 lathe.  Because the price of the inserts I tried to minimize their use, and developed a goo balance between cheap inserts, HSS and the Kinnemetal ones.

I agree that the trigon insert is superior to the triangle, because it is stronger, but I' don't have a holder for them.

Here's a bit of a kicker:  The K tool holders aren't much more costly than any of the mid-range tool holders.  I am looking to start tooling for CNMG for my bigger lathe and The holders are quite reasonable in price.

I've only had one time where the triangle tool was not up to the task:  an 8" diameter 4140 PH steel pipe section I was trying to chamfer. The lath was just too flimsy for the tool pressure required on my 12X37, and I fractured the insert.  Repeatedly.

If you have a small lathe, know that the cutting depths needed to really take advantage of carbide can be very hard or impossible if you lathe isn't rigid enough.  You can help fix this by using inserts ground for finish on aluminum - for steel, but know they have a shortened life, but will work well.


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## David_R8 (Nov 16, 2022)

I did a bunch of research on insert tooling and one key learning was that the nose radius is the minimum depth of cut. This has a lot of implications for us small lathe owners. If the radius is too large then there's a good possibility that the machine won't be able to make that depth of cut. 
All of this lead me to use HSS far more than insert tooling simply because I can keep it razor sharp and take depths of cut that my South Bend 10K can manage.


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## Susquatch (Nov 16, 2022)

little ol' e said:


> Without focusing on a brand of insert here....
> These are my go to inserts daily for turning. Both CNC and manually.
> They are mid grade with several layers of coating.



Hey Eric, can you post part numbers for what you recommend as well as for the associated holders? 

I see you have several different types as well as several sizes of that type. With time I may come around to that but not just yet. I'd prefer to stick with one size and maybe several different point radii and maybe 3 types (Stainless, Steel, Aluminium) unless one type will do all which would be a bonus!


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## thestelster (Nov 16, 2022)

David_R8 said:


> I did a bunch of research on insert tooling and one key learning was that the nose radius is the minimum depth of cut. This has a lot of implications for us small lathe owners. If the radius is too large then there's a good possibility that the machine won't be able to make that depth of cut.
> All of this lead me to use HSS far more than insert tooling simply because I can keep it razor sharp and take depths of cut that my South Bend 10K can manage.


Hi David, I agree, but with too small of a nose radius, the finish isn't the best, unless you have a very slow feed, otherwise it almost looks like a super fine thread.  According to the Sandvik Handbook:


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## David_R8 (Nov 16, 2022)

thestelster said:


> Hi David, I agree, but with too small of a nose radius, the finish isn't the best, unless you have a very slow feed, otherwise it almost looks like a super fine thread.  According to the Sandvik Handbook:
> 
> View attachment 27976


Definitely, I round over the nose slightly to avoid that exact problem. For a finishing pass I will set the feed rate very slow, I have the ability to set a rate as fine as .0015"/rev which is obviously pretty glacial and  I can't say that I've ever used it.


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## thestelster (Nov 16, 2022)

Also, have a look at those red arrows in the Sandvik Nose Radius picture.  The size of those arrows is of significance!  With a shallow depth of cut, *relative to the nose radius*, the radial forces created are larger than the axial.  This will cause chatter, especially with slender parts.  But when we take a deeper depth of cut, *relative to the nose radius*, the axial and radial forces are almost equal, therefore far less tendency for chatter. 






The same goes for lead angle.  If we can have the majority of the forces directed towards the chuck, we should have less chatter, than if we had a tool entering at less than 90 degrees.  
(The picture of the "Small Angle" doesn't really describe this well).  In the picture of the 90degree lead angle, the vast majority of the forces are directed towards the headstock, (the heaviest and sturdiest part of our lathe), but with the "Small Angle", in the shown example 45degrees, the forces are directed towards the chuck *and* towards the part equally, therefore the resulting forces are off on an angle which would increase the propensity for chatter, especially on slender parts.


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## Susquatch (Nov 16, 2022)

Dabbler said:


> I'd like to add a comment, certainly out of order.



Out of order? NEVER! 



Dabbler said:


> I've used the cheapest of the cheap, mid-range and premium inserts over that last 40 years.  Yes even before ISO designations for inserts were commonly available sizes.
> 
> Here's my take for a hobby guy, and until tha last 14 years using a 1.5 HP lathe and 1 HP mill.
> 
> If you use the cheap ones carefully, they will get you by.  They are better than HSS in tough stuff like shafting (4330 in my case), but they don't last long and won't survive interrupted cuts or tough situations.



Yes, the cheapos have gotten me by so far too. I don't do a lot of tough stuff machining though so maybe I've been lucky. My nemesis is interrupted cuts like holes or keyway. I put the carbide away for that kind of thing now. 



Dabbler said:


> During all this time I also was using Kinnemetal tooling (holder and inserts) for a single tool, a triangle tool in my 12X37 lathe.  Because the price of the inserts I tried to minimize their use, and developed a goo balance between cheap inserts, HSS and the Kinnemetal ones.



Kind of where I am except nothing remotely like Kinnemetal here so my balance is between low cost inserts and HSS. 



Dabbler said:


> I agree that the trigon insert is superior to the triangle, because it is stronger, but I' don't have a holder for them.



I like what @John Conroy said about his diamond inserts. If I can make that work, I might give them a go.



Dabbler said:


> Here's a bit of a kicker:  The K tool holders aren't much more costly than any of the mid-range tool holders.  I am looking to start tooling for CNMG for my bigger lathe and The holders are quite reasonable in price.



OK, that got my attention. 



Dabbler said:


> I've only had one time where the triangle tool was not up to the task:  an 8" diameter 4140 PH steel pipe section I was trying to chamfer. The lath was just too flimsy for the tool pressure required on my 12X37, and I fractured the insert.  Repeatedly.



I did that with carbide end mills once. After two I was ultra careful. After 3 I changed to HSS and had no more problems. Not the same as what you describe, but I get it.... 



Dabbler said:


> If you have a small lathe, know that the cutting depths needed to really take advantage of carbide can be very hard or impossible if you lathe isn't rigid enough.  You can help fix this by using inserts ground for finish on aluminum - for steel, but know they have a shortened life, but will work well.



Hmmmmm. Seems counter intuitive but if it works it works!


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## Susquatch (Nov 16, 2022)

David_R8 said:


> the nose radius is the minimum depth of cut.



Hmmmmm.... Any idea why that might be?


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## David_R8 (Nov 16, 2022)

Susquatch said:


> Hmmmmm.... Any idea why that might be?


No idea to be honest but I expect it has to do with material engagement. If the DOC is less than the radius, I would think that the cutter would tend to 'ride' up and over the edge of the material.


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## thestelster (Nov 16, 2022)

Susquatch said:


> Out of order? NEVER!
> 
> 
> 
> ...


The inserts designed for aluminium are extremely sharp with large angles.  Great for soft materials, but easily chipped with steel, unless you take very shallow cuts.


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## thestelster (Nov 16, 2022)

Susquatch said:


> Hmmmmm.... Any idea why that might be?


Have a look at post #163.


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## DPittman (Nov 16, 2022)

Susquatch said:


> I don't do a lot of tough stuff machining though so maybe I've been lucky.


I dunno....machining bolts can be pretty tough.  I'm sure the quality of the bolt makes a difference but the ones I've done are usually a hard go.


----------



## PeterT (Nov 16, 2022)

Machining bolts? I don't get it. Using them up as a source of grade round stock or...?


----------



## Susquatch (Nov 16, 2022)

DPittman said:


> I dunno....machining bolts can be pretty tough.  I'm sure the quality of the bolt makes a difference but the ones I've done are usually a hard go.



You are right. I machine a lot of bolts. Most are old soft bolts but many are Grade 8.

Ok, I take it back. Now I'm even more lost.


----------



## Dabbler (Nov 16, 2022)

I machine bolts all the time.  Shorten them.  Flatten out their heads.  Make a cap head bolt just a *wee* smaller in diameter.  The options are unbounded!


----------



## Susquatch (Nov 16, 2022)

PeterT said:


> Machining bolts? I don't get it. Using them up as a source of grade round stock or...?



Yes. I get bolts at the machinery yards and even old machines out in the forest. 

Free stock. Simple as that.


----------



## DPittman (Nov 16, 2022)

Susquatch said:


> You are right. I machine a lot of bolts. Most are old soft bolts but many are Grade 8.
> 
> Ok, I take it back. Now I'm even more lost.


Maybe I should send you some titanium aircraft bolts and then you can really test inserts and hss on them.


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## little ol' e (Nov 16, 2022)

@thestelster, try not to overthink this if you can. I overthink all the time and it kills me sometimes.
 I know the brain sometimes needs to feel we are going by the book, but sometimes we need to throw the new books away and bring back the old ones....
Now where did I put my dam magnifying glass? The old books have such small letters...

The illustrations posted above are for optimum cutting conditions. It is very difficult to have every style insert, radius and holder at your disposal doing this as a hobby.

If you go by the book and illustrations above in order to find optimum cutting conditions for each part your machining in a hobby shop. You will be upside down on costs, along with piles of headaches trying to achieve the optimum cutting conditions in all types of materials.

Then you start thinking do I need a 90deg holder, 95 deg, 93 deg and so on.. looking for that optimum cutting condition.
Try not to let the " catalogue " mess you up.

Just know, when using indexable inserts, "especially nice new sharp ones..." be careful going into rads with them lol, plunge in with a nice used insert first it won't squack and chatter as much.
That's why I mentioned in the past, after roughing change the insert, after semi, change the insert but keep them aside for these types of applications.

Hobby guys, including myself, really need to stick to the basics when manual machining. Yes, indexable tooling is the way to go for roughing anything out quickly if your lathe can handle it.

 Finishing with .012-.015 stock leftover is great for a diamond finishing insert with a .015r which I think is optimum for stock to leave on my manual lathe without chatter.
That may be too much for some and not enough for others depending on the part being turned with inserts they have on hand. My rads have been plunged out by this point for blending since I have so many different types of inserts to choose from.

Bottom line here is, if you only have 1 or 2 style of holders and inserts to choose from, along with say a button cutter,
 your going to get some chatter.  Your going to get an insert into a full diameter radius eventually, simply because its easier then grinding several different rads continuously on HSS and blanks if your turning contours and shaping. Most guys find it much easier to just plunge in and done, then blend or polish it out.

I find rule of thumb's do not apply so much in manual turning.
CNC, yes follow rule of thumb 'n' toe...

Speaking of " Rule of Thumb "
When turning with inserts.  DavidR8 described it perfectly as mentioned above. If you have a .015 rad, take a minimum .015 DOC and so on.
I would say stick to insert rads that your lathe can handle in depths of cut. I can't say I follow the rules all the time thou..

Anyway, typing sucks on this end, I hope this shines some light on the illustrations with inserts.


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## Susquatch (Nov 16, 2022)

DPittman said:


> Maybe I should send you some titanium aircraft bolts and then you can really test inserts and hss on them.



If you look at the abs cutter I made, you can see a typical use of an old bolt. In fact, it still has the root of the old threads on it. It's just old steel, nothing fancy. But it's free. I think that's fairly typical of what I do. I usually part the head off and turn off the old threads to get a piece of rod I can use for other things. But sometimes the old head becomes part of whatever I am making. For example, my lathe height standard is just an old bolt with the head turned round to make a foot to sit on the ways.

I also do a lot of what @Dabbler describes - modifying a bolt for a special purpose.

Now that it's been pointed out, I'd bet a lot of my insert failures are the result of turning the odd grade 8 bolt into something more useful.

I bet I could find ways to use your titanium too.


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## David_R8 (Nov 16, 2022)

little ol' e said:


> Speaking of " Rule of Thumb "
> When turning with inserts.  DavidR8 described it perfectly as mentioned above. If you have a .015 rad, take a minimum .015 DOC and so on.
> 
> Anyway, typing sucks on this end, I hope this shines some light on the illustrations with inserts.


I learned a ton by watching Stefan Gottewinter here: 



The main point being that if you are using insert tooling, the nose radius is going to determine the minimum DOC. Without some planning it means that 'sneaking' up on the final dimension may be near impossible because the final pass might be less that the minimum DOC of the insert.
I had to learn to figure out my max DOC on the material and if the resulting final pass was going to be more or less than the minimum DOC. If less I'd change each DOC so that the lass pass was at the minimum DOC or slightly more.


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## PeterT (Nov 16, 2022)

Hmm.. for 'mystery metal' bolts, that could present any number of issues - unknown alloy, toughened skin, maybe slightly deformed, corrosion scale... all that good stuff. That sounds like a perfect application for HSS to rough it down, or maybe brazed carbide which are spit cheap & can be dressed with the right abrasive. Once you are beyond the bad stuff & hopefully more into the consistent core, then break out the inserts. Nothing saying it has to be one tool to do a job. Use the axe to fall the tree, save the fine chisels for when it becomes a plank LOL


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## little ol' e (Nov 16, 2022)

PeterT said:


> Hmm.. for 'mystery metal' bolts, that could present any number of issues - unknown alloy, toughened skin, maybe slightly deformed, corrosion scale... all that good stuff. That sounds like a perfect application for HSS to rough it down, or maybe brazed carbide which are spit cheap & can be dressed with the right abrasive. Once you are beyond the bad stuff & hopefully more into the consistent core, then break out the inserts. Nothing saying it has to be one tool to do a job. Use the axe to fall the tree, save the fine chisels for when it becomes a plank LOL
> View attachment 27980


For sure, sometimes I will throw my morning coffee at it, then my lunch...


----------



## Susquatch (Nov 16, 2022)

David_R8 said:


> The main point being that if you are using insert tooling, the nose radius is going to determine the minimum DOC. This may mean that 'sneaking' up on the final dimension may be near impossible because the final pass might be less that the minimum DOC of the insert.



I didn't see this in the video. (Yes, I watched the whole video.) I did understand his point about splitting the cut. It's a good lesson. Something I never did before but fully understood. I might try it more in more detail another day.

I guess I am a "forum idiot who sneaks up on my dimensions". However, I have only blown a few in a few decades so I'm not accepting his criticism. In fact, unless I'm missing something I'd say that I use the same technique on sneakups as he does with bigger cuts. Basically that is to measure, set a cut, take a cut, measure again, take the same cut or very close, measure again, etc. The key being to take the same cut so spring back etc are accounted for and you are not chasing your tail.

I can't wait to try it with bigger cuts. 

But I did not see anything in his video about this business of nose radius limiting the minimum cut.


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## David_R8 (Nov 16, 2022)

Susquatch said:


> I didn't see this in the video. (Yes, I watched the whole video.) I did understand his point about splitting the cut. It's a good lesson. Something I never did before but fully understood. I might try it more in more detail another day.
> 
> I guess I am a "forum idiot who sneaks up on my dimensions". However, I have only blown a few in a few decades so I'm not accepting his criticism. In fact, unless I'm missing something I'd say that I use the same technique on sneakups as he does with bigger cuts. Basically that is to measure, set a cut, take a cut, measure again, take the same cut or very close, measure again, etc. The key being to take the same cut so spring back etc are accounted for and you are not chasing your tail.
> 
> ...



I didn't learn the nose radius thing from Stefan. That I learned from folks over on Hobby Machinist when I asked why I missed dimensions. After explaing the setup, tooling and material someone said that the nose radius of that insert is xyz so any cut has to be at least that.
Then I was referred to that video as a primer on hitting dimensions.
Nothing more, nothing less and certainly not calling anyone an idiot. I'm just reflecting my learning about insert tooling...


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## little ol' e (Nov 16, 2022)

David_R8 said:


> After explaing the setup, tooling and material someone said that the nose radius of that insert is xyz so your last cut has to be at least that.


In theory that is what some think.
 You do have wiggle room with speeds and feeds with DOC's in any condition thou. Carbide needs a good amount of material to bite on, no question, otherwise your essentially grinding the insert away with shallow DOC's .
When taking under .01 with any insert, you end up wanting to increase the speed due to the surface finish becoming worse and worse, that's when people give up on indexable tooling and reach for the HSS in my experiences over the years.


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## Degen (Nov 16, 2022)

Do you sneak up on dimensions with HSS tooling?

How you cut whether you sneak up and account from give (spring back) in material's or do you do a cut to dimension without worrying about it.  No matter what you do all that matters is you do it consistently and you will get the results that you want.  Bounce back and forth so will your results.

Some of you have done one method or the other for years, stick with it as it works for you.


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## David_R8 (Nov 16, 2022)

Degen said:


> Do you sneak up on dimensions with HSS tooling?


I used to because I was afraid of overshooting. It's also a bit of a holdover from wood working where hitting a really precise dimension involves taking smaller and smaller cuts, using increasingly precise tools. Chop saw, --> hand saw, --> hand plane for example. 
It's a hard habit to break.


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## Degen (Nov 16, 2022)

little ol' e said:


> In theory that is what some think.
> You do have wiggle room with speeds and feeds with DOC's in any condition thou. Carbide needs a good amount of material to bite on, no question, otherwise your essentially grinding the insert away with shallow DOC's .
> When taking under .01 with any insert, you end up wanting to increase the speed due to the surface finish becoming worse and worse, that's when people give up on indexable tooling and reach for the HSS in my experiences over the years.


I'm surprised at your view on this, I regularly do cuts of 0.001" and achieve the results required along with great finishes.

My suspicion is that you have not set up tooling correctly, either too high or too low with carbide does effect finish quality greatly as it smears or grabs when cutting.  Correctly set up carbide cuts as it should.


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## Susquatch (Nov 16, 2022)

David_R8 said:


> Nothing more, nothing less and certainly not calling anyone an idiot.



Holy smokes. That was supposed to be a joke David! I never considered that you might think I took offense! Absolutely ZERO offense taken. My apologies for leading you or anyone else to think otherwise! 

OK, gotcha on the source of the nose radius limitation. But just so you know, I don't think that's right. I have not analysed it yet, but my instincts say that you have been misled. I'll think on it some more before and after falling asleep. Maybe @PeterT can help using his guru cad talents (if he feels like it). 

Perhaps a small insight into my thinking. While there is a little side pressure on the insert due to its right to left travel, this is minor compared to the cutting loads which are primarily down against the top of the insert as the part turns. Or looked at slightly differently, the insert cuts left only by the feed rate per revolution. However, the majority of the cut is the full circumference per feed unit left.

I'm still very pleased to finally understand where the folks who don't believe in sneaking up on dimensions are coming from. Can't wait to try their version of it. Heck, I might even change my process!


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## Canadium (Nov 16, 2022)

Susquatch said:


> I didn't see this in the video. (Yes, I watched the whole video.) I did understand his point about splitting the cut. It's a good lesson. Something I never did before but fully understood. I might try it more in more detail another day.
> 
> I guess I am a "forum idiot who sneaks up on my dimensions". However, I have only blown a few in a few decades so I'm not accepting his criticism. In fact, unless I'm missing something I'd say that I use the same technique on sneakups as he does with bigger cuts. Basically that is to measure, set a cut, take a cut, measure again, take the same cut or very close, measure again, etc. The key being to take the same cut so spring back etc are accounted for and you are not chasing your tail.
> 
> ...


@DavidR8 has probably been reading the David Best book on insert tooling where this is spelled out more thoroughly.


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## DPittman (Nov 16, 2022)

little ol' e said:


> For sure, sometimes I will throw my morning coffee at it, then my lunch...


Yes coffee makes everything run smoother, it's an excellent lubricant, especially for the mind.


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## David_R8 (Nov 16, 2022)

Canadium said:


> @DavidR8 has probably been reading the David Best book on insert tooling where this is spelled out more thoroughly.


I do own that book and it's an excellent reference.


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## Susquatch (Nov 16, 2022)

David_R8 said:


> I do own that book and it's an excellent reference.



Can either of you (@Canadium and @David_R8) explain it to me? I'm drifting off to sleep here. So far I don't get it. I don't think sleep is gunna change that.


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## PeterT (Nov 16, 2022)

little ol' e said:


> *Carbide needs a good amount of material to bite on, no question*, otherwise your essentially grinding the insert away with shallow DOC's .
> When taking under .01 with any insert, you end up wanting to increase the speed due to the surface finish becoming worse and worse, that's when people give up on indexable tooling and reach for the HSS in my experiences over the years.



This gets repeated often, but I am still struggling to understand why or what the basis is. I mentioned this in post #142 where I scribbled on the little operating window chart provided by carbide insert manufacturer. Particularly where I randomly flagged a faceted style finishing insert with a very small DOC range, 0.002-0.032" if I understand the specs correctly (excerpts below). There may be other carbides optimized with even smaller DOC than this, I just grabbed this one as example. This (0.002") seems to completely contradict 'a good amount of material'. Yes, there are heavy hogger carbides & I think that DOC is reflected in their respective operating plots, no? Isn't that how FT machinists choose tools?

Looking at this a different way, say you matched a HSS grind to dimensionally identically equal a carbide - rake, relief, nose radius, edge sharpness, surface finish.... (for now disregard carbides chip control features & coating to keep thing simple). What are we left with? The 2 tools differ only in their basic material properties: hardness & modulus & ?? Now all of a sudden they have dramatically different DOC 'bite'? That makes no sense to me. Now running them both for 1000 parts in production mode is a different thing. I'm just asking why does carbide 'need' a big bite?


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## PeterT (Nov 16, 2022)

I must admit I'm a bit confused by this particular graph because they kind of plop the various insert models over the operating range. Maybe more of a sales brochure format?
i.e. the X&Y axis is not a linear progression, it relates to the particular insert. But the way I interpret their operating range is the 2 corresponding shaded extensions. Maybe its 0.001-0.008"? I dunno
The other image is how Korloy & others display their graph, a little easier to digest


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## Dabbler (Nov 16, 2022)

From my experience of using carbide, even ground and polished ones, the DOC is only a small part of the story.  For a polished carbide insert to not 'skate' as I call it, or @little ol' e puts it 'grinds', you need pretty high RPMs and feed rates...

Maybe things have changed and newer specialized inserts may contradict  this, I'm fine with being wrong. 

But for an ali-express insert or even a mid range Kinnemetal insert (which is all I have direct experience with),  My minimum DOC is about 6-16 thou depending on the profile.  If I hone it to a sharp insert I can get away with .004-008 minimum DOC.  So for my purposes I never take less than .010 with a carbide insert, just to be safe.

With HSS, I can easily get to .001 min DOC.

So apart from making a theoretical discussion out of this, where's 'the meat'?  For a non-ground cheaper coated carbide insert, you need to take at least the radius, if not more, which for the insets I buy is still a hefty chunk, around .010-.018 [correction]  

For a ground an polished insert I take about .010 - no less certainly.  I just have to plan my turning accordingly and leave enough for filing and honing as required.


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## PeterT (Nov 16, 2022)

Dabbler said:


> From my experience of using carbide, even ground and polished ones, the DOC is only a small part of the story.  For a polished carbide insert to not 'skate' as I call it, or @little ol' e puts it 'grinds', you need pretty high RPMs and feed rates...
> 
> But for an ali-express insert or even a mid range Kinnemetal insert (which is all I have direct experience with),  My minimum DOC is about 6-16 thou depending on the profile.  If I hone it to a sharp insert I can get away with .004-008 minimum DOC.  So for my purposes I never take less than .010 with a carbide insert, just to be safe.
> 
> ...



I will reference a different but well known manufacturer, Korloy. Their operating charts are a bit more straightforward to read. I'll do some metric to imperial conversions just for consistency (so check my math haha). These are off the shelf lathe inserts. I just pulled a few random ones that had the application 'finishing' in their description. I'm trying to direct attention to what the manufacturer recommends for feed (Fn) and depth of cut, DOC (ap) vs. the narrative discussion thus far, what people claim or have experienced as 'minimums'. Again, if I am out to lunch let me know. I'm just conveying what is in the specs.

First off, I recall my 14x40 lathe has a power feed range of 0.003 - 0.086 inch/rev. That works out to .076 - 2.184 mm/rev so on Korloy application chart, roughly the blue box. That seems to be in a useable range of many carbide choices, just perusing the offerings. Some are outside the range as would be expected, so don't run those.





So here are some random finishers. Behind the scenes they vary by other sub-criteria - material suitability, coating, nose radius, rake geometry, chip control, blah-blah
I picked the low Fn & ap values off the respective blue/green bars & converted to imperial cells on right cells.
So in this example Fn=0.002 in/rev, DOC=0.004"





Some more. I actually use the AK myself for aluminum. It says DOC=0.004" but I can tell you (or show you next visit) a thou comes off as a tiny continuous thread. If I change feed & take off the hilltops I'm pretty sure its half that, 0.0005". On that basis, and I am only guessing here, I don't think the operating bars are hard stop do-not-pass limits. Obviously its peeling off a thou, just like you know your HSS is peeling off a thou. The bars (or operating windows on other vendors) is probably for guidance, or maybe extended tool life, or other factors important for manufacturing, I dunno. The point is, these DOC examples are not 10,20,30 thou just because its carbide.
Note the 2nd pic KF, insert. Min DOC = 0.0004" I have seen that style in Ali / Ebay lurkings. So I don't think they are super exotic or even 'new'. Now one could argue that Fn is very fine, outside the range of hobby lathe. But again will it be 'pretty good' at my min feed? I would wager a coffee yes.






Example on the other end of the range, cited for heavy duty cutting. Minimum DOC of 0.275" That is a hefy bite. Very different cutting geometry as would be expected.
I hope you see where I'm going with this. On one end of the carbide spectrum are Finishers. On the other end are Roughers. In between is a bazillion other inserts. Which one do you have & what is the corresponding operating window?


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## Canadium (Nov 17, 2022)

At one extreme too fast rpm results in too much heat which results in a poorer result. At the other extreme too slow rpm will fail to cut and just rub or cut intermittently. The "ideal" rpm can be estimated by a simple formula RPM=(SFM/D)X3.82
SFM=surface feet per minute
D=diameter of workpiece in inches
3.82 = a constant derived from more complex formula RPM=(SFMX12)/(DXpi)

This does not account for differences caused by differences in quality of the material machined which is typically given as a table of material vs ideal SFM to KISS


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## Degen (Nov 17, 2022)

Canadium said:


> At one extreme too fast rpm results in too much heat which results in a poorer result. At the other extreme too slow rpm will fail to cut and just rub or cut intermittently. The "ideal" rpm can be estimated by a simple formula RPM=(SFM/D)X3.82
> SFM=surface feet per minute
> D=diameter of workpiece in inches
> 3.82 = a constant derived from more complex formula RPM=(SFMX12)/(DXpi)
> ...


Points to one thing I've mention all along,   coolant/lubrication  is important particularly for carbide cutting results vs wear prevention on HSS.


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## Susquatch (Nov 17, 2022)

PeterT said:


> I hope you see where I'm going with this. On one end of the carbide spectrum are Finishers. On the other end are Roughers. In between is a bazillion other inserts. Which one do you have & what is the corresponding operating window?



I like your thinking Peter. 

Ever since we came down out of the trees, humans have had a long history of challenging accepted facts, evolving our knowledge, and creating new knowledge. As you know, I love sayings. The one that comes to mind in this case is: Many an impossible thing has been done by someone who didn't know it was impossible. 

I have always accepted the direction that says Carbide can't handle small cuts and learned to live with it. But my views are changing. The day that @Dabbler talked about honing carbide was an eye opener for me. In fact, just yesterday I tried sharpening a carbide threading insert. It was an eye opener. I got nowhere. I plan to try a diamond wheel or a diamond hone next. 

In the process of deciding what grind I should be shooting for, I had a good look at the old edge with a 20x jewelers loop. It was unmistakably rounded vs what a sharp HSS threading tool looks like. So I plan to try to make it sharp and we will see how it works. 

In the meantime I thought a little about the conventional sintering process used to make carbide inserts. A sharp edge would be difficult to make easily. Then the question of edge durability for sintered parts passed through my mind with a similar ending. Inherently difficult to maintain an edge. 

So it's not hard to see why and how early carbide or cheap carbide might have developed a reputation for poor sharp performance. 

The terminology that @little ol' e & @Dabbler use are also informative - or at least provide a bit of a window into how they visualize a carbide insert cutting steel at the margins of its capability. Rubbing in one case, skating in the other. Both are excellent ways to visualize a failure to "bite". 

No matter what our knowledge levels, I think the majority of machinists can appreciate the differences in the way various solid materials cut. I'll arbitrarily put rubber at one end and diamond at the other. Additionally, we can all appreciate the way that different materials interact with each other in a cutting process. 

I think you are probably onto something. The mere fact that you have found documented examples of Carbide inserts that are recommended by their manufacturer for use at low depths of cut is compelling to me. 

It might be time to put that old knowledge which says that carbide cannot make tiny cuts away and accept that the world is round. Maybe the correct question isn't can carbide make shallow cuts, maybe the correct question is which carbide insert do I use to make shallow cuts? 

All great musing. 

I just want to know which quality holder and inserts to buy to expand my machining horizons and improve my carbide machining horizons.


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## Canadium (Nov 17, 2022)

Susquatch said:


> I just want to know which quality holder and inserts to buy to expand my machining horizons and improve my carbide machining horizons.



About half of the David Best book is recommendations.


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## Susquatch (Nov 17, 2022)

Canadium said:


> About half of the David Best book is recommendations.



OK...... Now you have my undivided attention. 

Just so you know, I really like books. I have a nice library that will heat the house for 5 years after they bury me. 

How old is this book? Does it know what @PeterT has been talking about? Or does it still think the sun orbits the earth?

I know, I know, I know...... Does anyone know what Peter is talking about??? 

JKg Peter!

Gunna go find this book right now..... 

Ps - I totally love that book you folks pointed me at - Beyond Measure by James Vincent. Fantastic read.


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## Susquatch (Nov 17, 2022)

@Canadium - it is $75 Canadian. Is it really worth that much?


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## Canadium (Nov 17, 2022)

Susquatch said:


> @Canadium - it is $75 Canadian. Is it really worth that much?


Hmmm ... I think value is an individual thing. Depends a lot on your expectations.  I love books, saw many positive reviews, and I didn't see many others on the subject so I bought it. Learned quite a bit from it and probably will learn more as I reread multiple times. I'm not sorry I bought it. I've paid a lot more for books in the past. There are only 105 pages so if you think like a librarian and weigh value by number of pages you might not go for it.


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## Susquatch (Nov 17, 2022)

Canadium said:


> I'm not sorry I bought it.



That's good enough for me.



Canadium said:


> I've paid a lot more for books in the past.



Me too. My machinery handbook was prolly the most I ever spent on myself besides university text books. At the office we bought whatever we needed - I once bought a full set of the Oxford Dictionaries. Several grand right there. But nobody would ever argue their authority.

I wish I could have brought them home with me when I retired.


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## PeterT (Nov 17, 2022)

Canadium said:


> About half of the David Best book is recommendations.



I know him from Hobby Machinist forum. He has done some really cool machine builds. Usually I throw money at books but strangely (for me) I did not click buy. I suppose price was a factor. Thought I'd wait for a few reviews, then I kind of forgot about it.


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## Tecnico (Nov 17, 2022)

Just want to say this thread is full of interesting information.  I'm going to have to block off some time to go through all the references.

Keep it coming!

D


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## Canadium (Nov 17, 2022)

PeterT said:


> This gets repeated often, but I am still struggling to understand why or what the basis is. I mentioned this in post #142 where I scribbled on the little operating window chart provided by carbide insert manufacturer. Particularly where I randomly flagged a faceted style finishing insert with a very small DOC range, 0.002-0.032" if I understand the specs correctly (excerpts below). There may be other carbides optimized with even smaller DOC than this, I just grabbed this one as example. This (0.002") seems to completely contradict 'a good amount of material'. Yes, there are heavy hogger carbides & I think that DOC is reflected in their respective operating plots, no? Isn't that how FT machinists choose tools?
> 
> Looking at this a different way, say you matched a HSS grind to dimensionally identically equal a carbide - rake, relief, nose radius, edge sharpness, surface finish.... (for now disregard carbides chip control features & coating to keep thing simple). What are we left with? The 2 tools differ only in their basic material properties: hardness & modulus & ?? Now all of a sudden they have dramatically different DOC 'bite'? That makes no sense to me. Now running them both for 1000 parts in production mode is a different thing. I'm just asking why does carbide 'need' a big bite?


I'm guessing the answer to your question is that because carbide is more brittle than HSS originally they were making inserts with bigger nose radius and duller cutting edges hence deeper depth of cut required and hence the reputation. Things change however and they now make better carbide compositions and as you point out finishing inserts.


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## Susquatch (Nov 17, 2022)

Canadium said:


> I'm guessing the answer to your question is that because carbide is more brittle than HSS originally they were making inserts with bigger nose radius and duller cutting edges hence deeper depth of cut required and hence the reputation. Things change however and they now make better carbide compositions and as you point out finishing inserts.



I need to learn how to write simpler and better. That's basically what I said except I took 16 pages to say it.


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## PeterT (Nov 17, 2022)

Here is where I think 'speed' is entering the picture & probably influencing the consensus that carbides are outside the realm of hobby machines. BTW I shared this same view because that's what the manufacturers data suggests (and still does, read on). That is until I started using specific carbides myself and what can I say, the results don't lie. I've ran the same insert many many times, in different common materials, taken a thou off, measured the results. Its reality, no different than when I did the exact same thing with HSS. So possibly, as I mentioned before, perhaps the manufacturer operating parameters (bounding area graphs, bar charts, min/max) are not absolutes or hard boundaries. They could be softer edge boundaries that 'work' on the fringe or even outside the range to some extent, but other factors (disadvantages) may start to enter the picture.

Korloy example. I lifted this chart which shows cutting speed on Y axis. It shows a range of inserts & corresponding materials. Just for visual reference I made a line at 100 m/min.





Now I plug in some numbers (red cells), a recommended surface speed from chart, a bar diameter & compute resultant RPM which is what I need to set on my lathe
Here we see the issue. My lathe can run between 70-1350 RPM. The calculated resultant rotational speed is already 1273 RPM, 94% of my top speed. 





Worse yet, make the diameter smaller & RPM climbs accordingly





Working backwards, if I set RPM to max, what is the resultant surface speed? (approximate)





using above example, shows as green line





This is what I'm wondering out loud. Is the boundary hard (manufacturer blue) or is the boundary soft (orange shade just for visualization). 
Because going back to my original statement, there are millions of everyday examples where hobby machinist are happily cutting materials to a satisfactory combination of finish & dimension. So somehow the data has to facilitate that reality.





Its unfortunate that an equivalent diagram isn't readily available for HSS. Or maybe it is, tucked away in a text book. Because an 'overlay' would be inteersting
I'd like to hear from people who have been down this path where this is familiar territory, maybe do it for a living. Is this the workflow of how they select carbide cutting tools? What are typical spindle speeds of CNC lathes?


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## PeterT (Nov 17, 2022)

btw, the Korloy documentation does have generic charts & discussion about the tradeoffs of different machining parameters. I'm sure other suppliers do much the same






This kind of table shows feed & cutting speed by insert. They don't really say min/max/average but presumably corresponds to the graphs & bar format
What's interesting is once you zoom in or define operating parameters, there are many available corresponding insert shapes that satisfy that same criteria.


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## Canadium (Nov 17, 2022)

Susquatch said:


> I need to learn how to write simpler and better. That's basically what I said except I took 16 pages to say it.


Sorry! I have to learn to read better!


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## little ol' e (Nov 17, 2022)

Degen said:


> I'm surprised at your view on this, I regularly do cuts of 0.001" and achieve the results required along with great finishes.
> 
> My suspicion is that you have not set up tooling correctly, either too high or too low with carbide does effect finish quality greatly as it smears or grabs when cutting.  Correctly set up carbide cuts as it should.



What tool, insert grade and material are you taking the .001 DOC in to get the nice finish? Can you give us the speed and feed you were running that particular cutter at as well please?
I do not know of any indexable tool/insert that will perform well in steels when trying to skim .001, I will certainly give it a try.
Thanks!


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## Degen (Nov 17, 2022)

little ol' e said:


> What tool, insert grade and material are you taking the .001 DOC in to get the nice finish? Can you give us the speed and feed you were running that particular cutter at as well please?
> I do not know of any indexable tool/insert that will perform well in steels when trying to skim .001, I will certainly give it a try.
> Thanks!


Steel was 4140 - about 6" dia speed about 360 rpm, feed slow don't remember, insert triangular, style don't remember other than non coated and extremely limited options of inserts because of size (one of my first insert cutters) on the Logan Model 200.  Light passes done without lube.

I was surprised at the ease of the cut and finish produced

Biggest thing is ensuring proper cutter height, high tends to smear (not enough pressure on edge as its distributed over a larger area), low tends to grab (too much pressure because too little insert is in contact).


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## little ol' e (Nov 17, 2022)

Ok gotcha, thanks.


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## Susquatch (Nov 17, 2022)

thestelster said:


> Here is a link to the Sandvik Turning Handbook:
> 
> https://coromantstrgprod.blob.core.windows.net/publications/92df68b7-b8c0-494d-b290-e27f540b5885.pdf?sv=2021-06-08&st=2022-11-16T18:44:59Z&se=2022-11-16T20:49:59Z&sr=b&sp=r&rscd=inline;+filename=C-1020-18.pdf&rsct=application/pdf&sig=t+nlI3N0olYsL5dm9B6aRAK1xQ4IJyMVUl6z/8pLio0=



The link doesn't work @thestelster.


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## thestelster (Nov 17, 2022)

Susquatch said:


> The link doesn't work @thestelster.


Hmmm... I checked it yesterday and it was working.  I tried to attach it as a PDF as well, but the file was too large.  You'll have to Google it.  Sorry.


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## little ol' e (Nov 18, 2022)

PeterT said:


> This gets repeated often, but I am still struggling to understand why or what the basis is. I mentioned this in post #142 where I scribbled on the little operating window chart provided by carbide insert manufacturer. Particularly where I randomly flagged a faceted style finishing insert with a very small DOC range, 0.002-0.032" if I understand the specs correctly (excerpts below). There may be other carbides optimized with even smaller DOC than this, I just grabbed this one as example. This (0.002") seems to completely contradict 'a good amount of material'. Yes, there are heavy hogger carbides & I think that DOC is reflected in their respective operating plots, no? Isn't that how FT machinists choose tools?
> 
> Looking at this a different way, say you matched a HSS grind to dimensionally identically equal a carbide - rake, relief, nose radius, edge sharpness, surface finish.... (for now disregard carbides chip control features & coating to keep thing simple). What are we left with? The 2 tools differ only in their basic material properties: hardness & modulus & ?? Now all of a sudden they have dramatically different DOC 'bite'? That makes no sense to me. Now running them both for 1000 parts in production mode is a different thing. I'm just asking why does carbide 'need' a big bite?


Hey Peter,

If your looking for inserts that can turn .001 they can be had for around $260 each. They are specifically for hard turning on CNC.  Those inserts are not carbide or coated carbide . Those are ceramics and CBN's, not what your going to be running on a manual lathe IMO.
 Not to say some aren't doing it.  I don't, simply because, my manual lathe couldn't handle it, and to be honest, I don't know of a manual lathe that could handle those inserts.

I figured this thread was about manual machining- turning inserts.  That is why I tried to simplify things in 3 categories when considering carbide inserts.

I also posted a photo of the main 4 inserts I use on my manual lathe, that I felt others could benefit by. 
The two triangular inserts with a .03 rad for roughing and semi, along with two triangular inserts for finishing with a .015 rad.

Just pick a holder and insert of choice that matches best with what material you happen to be machining.
I think I posted what materials the 3 simplified grades would perform well in as well IIRC...
If I didn't, let me know.

-When you ask why does carbide 'need' a big bite. -

Carbide inserts in its form, is a compressed dense material, some think its brittle.
This is why Carbide needs to be engaged into the material to keep everything stable, this is why we always like to leave at least .012 - .015 for a finishing inserts.
Can you take a lighter DOC with a carbide insert, of course you can, as long as you back the RPM down while keeping the feedrate up for the bite to happen. That way your not grinding, skating or rubbing rather than cutting.

Does that explain things any better and make sense?


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## little ol' e (Nov 18, 2022)

Susquatch said:


> Hey Eric, can you post part numbers for what you recommend as well as for the associated holders?
> 
> I see you have several different types as well as several sizes of that type. With time I may come around to that but not just yet. I'd prefer to stick with one size and maybe several different point radii and maybe 3 types (Stainless, Steel, Aluminium) unless one type will do all which would be a bonus!


I missed seeing your post Susquatch, these pages go by quicker than I can type ... I hope to stay in line here eventually haha

Unfortunately, I have not come across any 1 insert that will work well for all 3 material groups yet lol . I wish...
Could get away with 1 insert for like 304 stainless, P20 , 4140  but that's pushin' it really.

Depending on the diameters your machining, I like to have 2 sizes triangular for roughing, and 2 sizes for finishing since my diameters can be anywhere from a 1/4" round  up to 6".

Not sure what your budget is but if you could let me know what your lathe specs are I'm sure we could pick something out together that would work.

Just need a couple weeks to get caught up on a few things.
 I also need to get something sent out to another member here to try that has been sitting on my desk for well over a week now, my wife has been sick so... I only have 2 hands and 1 is usually half full


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## gerritv (Nov 18, 2022)

Susquatch said:


> The link doesn't work @thestelster.


The way to get there has been posted multiple times by me. https://www.sandvik.coromant.com/en-gb/downloads/ . select Technical Documents in the filter and browse for the book. they prevent you from using direct links.


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## PeterT (Nov 18, 2022)

little ol' e said:


> This is why Carbide needs to be engaged into the material to keep everything stable, this is why we always like to leave at least .012 - .015 for a finishing inserts.
> Can you take a lighter DOC with a carbide insert, of course you can, as long as you back the RPM down while keeping the feedrate up for the bite to happen. That way your not grinding, skating or rubbing rather than cutting.



The 0.001" DOC kind of came out as home machinist shop example we can relate to. We know from experience we can shave off that much off with HSS tool. I've done it myself, I'm familiar with it, I'm not opposed to it. I just added that I also shave that amount off with carbide inserts. Many, many times. Which differs from experiences that you can't, or not for long, or special inserts or mods are required. I probably do 60/40 aluminum alloys / other. But other are mild steel, tool steel, occasional 4140, brass, bronze etc. Sorry no rusty bolts from the forest haha. I don't think my micrometer or DRO is lying or I would not have gotten very far in machining, so what remains is explaining it. Because as I mentioned, it doesn't agree with the insert catalogs so there must be more to the story. BTW when I tried braze on carbides I hated them. I went back to HSS. Those carbides seemed to be very friable (edges chipped easily). I chocked it up to offshore quality because I tried a better USA braze-on & it was much better, but also more expensive. Then I tried some CCMT for both OD turning & boring bars. Some cut better than others, as one would expect, but basically I never looked back.

My vocabulary/web plagiarism might not be quite right but I'll give it a shot. Hardness is the ability of a material to resist deformation. Brittleness is relative inability to sustain plastic deformation before fracture of material occurs. Modulus is the slope of stress/strain curve before elastic deviation occurs. Toughness is the ability of a material to absorb energy and plastically deform without fracturing, the area under the stress strain curve. Ceramics for example are very hard, harder than most tool steels. That property makes for a good cutting edge. But they are also brittle, therefore when it fails the fractured edge no longer resembles a useful tool. Hardness & brittleness generally correlate in many natural materials.

So the way I visualize it, HSS can be conditioned to a razor edge. It is tough & can withstand rough & tumble machining, vibration, harmonics. Its going up & down the more ductile green curve & absorbs more energy doing so. A disadvantage might be how long does the edge last? Its softer by definition. The HSS edge may not be fracturing but its rounding over by abrasion. There is no free ride. It may behave differently at elevated temperature, more time consuming to create &re-create geometry...but now we're getting into the weeds












But here is what I was wondering. Lets say we operate a carbide & HSS in the red box, meaning stress level. Same tool geometry. Neither tool edge has failed. Maybe I'm operating in that zone?
I can think of lots of reasons why ceramic would get pushed into failure, wrong insert geometry for DOC, loose lathe ways, highly interrupted cutting....


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## PeterT (Nov 18, 2022)

little ol' e said:


> If your looking for inserts that can turn .001 they can be had for around $260 each. They are specifically for hard turning on CNC.  Those inserts are not carbide or coated carbide . Those are ceramics and CBN's, not what your going to be running on a manual lathe IMO.  Not to say some aren't doing it.  I don't, simply because, my manual lathe couldn't handle it, and to be honest, I don't know of a manual lathe that could handle those inserts.



Like I mentioned above, the 0.001" was maybe more of a discussion parameter or what we achieved in the shop vs. a specific shopping list requirement. At least from my perspective. But the random finishing carbides I pulled from the Korloy catalog are not exotic, they are pretty common off the shelf inserts AFAIK. $260 would buy me about 100 of them LOL. I'm just saying many are referenced in the 0.1mm (~0.004") DOC range as per manufacturer minimum. And I am guessing they are conservative to keep customers happy. I don't think they explode with 0.002" DOC and now the gap is narrowing. For sure many inserts show higher recommended DOC, but its all spelled out in the catalogs. Now if you buy some random inserts with no corresponding part number or specs, then yeah, could be a bad machining experience. No different than grinding a HSS with incorrect rake geometry or tool placement.


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## Susquatch (Nov 18, 2022)

thestelster said:


> Have a look at post #163.



I am sorry to take so long replying to your post. I confess that I have been studying the material you provided in post 163 in my mind all afternoon and all night.

I almost want to keep my mouth shut...... but can't. My own need to understand exceeds the embarrassment of the admission.

I believe the photos and the implications and conclusions Sandvik provides in a few of those photos is wrong......

I know, I know. Who am I to challenge the technical information provided by the likes of Sandvik...... But I've looked at it every which way of Sunday and I keep concluding the same thing.

Perhaps I am missing something. If so, I'd sure like to know what it is.

How can Sandvik be wrong? These characters are insert experts! How can I be right when I am not worthy to walk in their shadow?

Perhaps so, but I know from my own personal experience in the auto industry that the marketing folks often take complicated technical information and turn it into simplified information that is just plain wrong. If I am correct in my assessment of this particular information, then I'd bet that is what has happened at Sandvik too.

Please look at the drawings closely to see if you see what I see. First and foremost, (and what caught my attention in the first place), I see an insert that is cutting air, not metal. There should be metal above the insert that subsequently gets peeled away by the insert. If there is nothing above the insert as shown in their drawings, then there will be no chip. But yet, they show a chip anyway as though it will magically appear out of thin air. In my opinion, the shape and location of the cut section is correct, but only for below the insert. Above it, the shape is also correct but should be shifted to the right by the feed rate. What they show is what it would look like if the feed was disengaged and the lathe left to run for at least one revolution. In this case the cut is already completed, the forces are all gone, and there is no chip.

In my view, the problem that results from this error, is that the resulting forces are shown incorrectly too and so is their derivation and their consequences. 

The description completely ignores the downward force on the top of the insert. This force is not minor. In fact, I believe it is the dominant cutting/shearing force by a VERY wide margin. In my mind, it is unreasonable and misleading to ignore this dominant force in any discussion of insert performance and resulting forces. Furthermore, I believe it is the downward cutting force that drives all the issues that we have been discussing here. I'm not saying that the other two forces don't play a role, just that I believe that their role is minor compared to the cutting/shearing force itself. Basically, they guide and direct the cutting force, and I don't think they really do much more than that. 






When I think about forces and the structure needed to support those forces, there is no rock of Gibraltar to the right or front of the tool. The vast majority of the support structure is under the tool down through the cross-slide to the bed because that's where the vast majority of the forces are and must be reacted.


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## little ol' e (Nov 18, 2022)

@PeterT,

IMO, these companies that produce  these catalogues with a high degree of technical references regarding " Optimal cutting conditions", with emphasis on tool life in many different types of materials both soft and hard, is just ridiculous.

Some, well most of what is printed, really doesn't make sense in my experience with indexable tooling, and the way I would machine something.
Having said that, this is only my opinion along with others that I have trained over the years... Hmmm, that could be a bad thing eh!

Like I mentioned before, you can get technical to a high degree on paper and with images, but in reality, it just doesn't make sense to me.
For the machining I do, I can always make something work as most of us can and do.

If you have good luck with machining .001 with indexable inserts with your machines and tooling, then that's great its working for you.
For me, that is grinding/skating as some would say at that point, wearing an insert quickly for no reason, it isn't machining.

Respectfully,
Eric


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## Degen (Nov 18, 2022)

little ol' e said:


> @PeterT,
> 
> IMO, these companies that produce  these catalogues with a high degree of technical references regarding " Optimal cutting conditions", with emphasis on tool life in many different types of materials both soft and hard, is just ridiculous.
> 
> ...


The companies produce these guides so their products perform if someone follows them.

However what they don't tell you is how to maximize performance.  This takes experimentation to achieve the best results.

Good example is watching some of Titan of CNC on how he pushes tooling well beyond the published limits while maintain results and life of tooling.

Think of the publications as the starting point, the rest is up to you on how far you can take it.


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## Susquatch (Nov 20, 2022)

@DPittman - I think you were right.

A farming neighbour dropped these off this morning for me. I've done a few repairs for him so it's a bit of a thank you. They would have hit the scrap yard for peanuts otherwise.






Very typical of the majority of my stock. This haul is all 7/8ths and 3/4.  Most are fine thread which suggests harder steel. I like the long shanks cuz I can do more with them.

Lots of really cool projects hiding inside those old bolts! 

But ya, gunna be hard on cheap inserts.


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## little ol' e (Nov 20, 2022)

Degen said:


> The companies produce these guides so their products perform if someone follows them.



Ok, fair nuff;

If a tool guy comes into your shop, says he has the latest and greatest inserts for what your machining. The conversation leads to him viewing your 4 sided indexable inserts both roughing and finishing. ( forget milling or turning here, just talking inserts)
Then he suggests an 8 sided insert for just a few dollars more, explaining the 4x more cutting edges saving you money in the long run for just a few dollars more each... Adding about $30 to a box of 10... along with the possibility of a new holder as well.
Would you buy them?

How about a finishing insert,
 Capable of machining a pass at .001 in mutliple grades for multiple applications... Lets just throw Korloy, Seco and Kyocera brands into the mix here since it appears most are looking in that direction here. Heck, lets throw all the Aliexpress offerings into the mix as well.
 Would you buy those inserts given your machining experience and background of using indexable inserts as often as you do ?

1 final question,
With what I mentioned above, even if the inserts do perform as they say out of the box... do you feel as thou these descriptions are geared for CNC machinists, manual machinists or both alike?

Too all the experienced machinists here,
 PLEASE, add your comments if you have been holding back in this thread to help others just getting started using indexable tooling with manual machines.

Thanks,
Eric


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## PeterT (Nov 20, 2022)

little ol' e said:


> @PeterT,
> If you have good luck with machining .001 with indexable inserts with your machines and tooling, then that's great its working for you.
> For me, that is grinding/skating as some would say at that point, wearing an insert quickly for no reason, it isn't machining.


I got thinking about my radial engine project. I used a HSS (for turning) exactly twice - a boring bar tool to recess the crankcase ID & parting blade outside the range of my carbide. My lathe is a '97 Taiwan 14x40, nothing special. Most turning tolerances are within a thou, many tighter. I literally could count months before an insert was swapped due to wear or chip. Other hobbyist hobby projects may be a completely different combination of materials & machines, so their results may well vary. I also recognize some mind blowing model engineer projects & tooling were done entirely with HSS back in the day. However, that was when HSS was ubiquitous, abundant, cheap, higher quality and generally corresponded with the toolholders of the era. Anyway, time for me to bow out of this discussion. I think it ran its course.


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## little ol' e (Nov 20, 2022)

PeterT said:


> Anyway, time for me to bow out of this discussion. I think it ran its course.


X2 
 All the best guys !


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## Degen (Nov 20, 2022)

little ol' e said:


> Ok, fair nuff;
> 
> If a tool guy comes into your shop, says he has the latest and greatest inserts for what your machining. The conversation leads to him viewing your 4 sided indexable inserts both roughing and finishing. ( forget milling or turning here, just talking inserts)
> Then he suggests an 8 sided insert for just a few dollars more, explaining the 4x more cutting edges saving you money in the long run for just a few dollars more each... Adding about $30 to a box of 10... along with the possibility of a new holder as well.
> ...


All of these valid questions, I change and experiment to get the results I need.   I tend to stick to reputable sources, as I have a repeatability if it works factor.

Difference between manual vs CNC is CNC shows up the faults and benefits faster,  but the suggestions that apply to one apply to the other.  So in short if it works stick with it, if it does start experimenting to get the results you desire, follow a methodology that works for you.

This isn't rocket science that you are making it out to be.


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## little ol' e (Nov 20, 2022)

Degen said:


> This isn't rocket science that you are making it out to be.



You are absolutely correct with this statement.
 That is why I suggested a mid grade substrate with a decent coating, without making things complicated. Due diligence plays a roll in any that are interested, taking in information along with misinformation to reach a decision, then ask questions.

PeterT for example, needs more concrete facts as to why things look and appear the way they do in catalogues... Not enough hours in the day to even begin a conversation like that unless you have a good start point.

HSS, carbide blanks and cheap inserts certainly are a good start point, but no where near the advanced coatings and substrates used today.
The inserts of " Yesterday " with TIALN coatings and such are a good alternative to a 1 up head start into machining quicker, with instant results rather than grinding cutters that just don't really perform that well these days due to the lower percentages of cobalt added, especially with the cheaper stuff as I mentioned earlier in this thread. 
What cobalt content does Aliexpress HSS cutters have? Maybe 2%... I dunno, I never used bought or tried it. But it works so that's great news. 

But I spoke prematurely on many things I posted, I really need to learn more about coatings and substrates with inserts as someone suggested in an earlier post, perhaps ?

Certainly not rocket science, but, I may have to learn/know how to index and set a tool properly to make this happen as you suggested earlier in a post.

Point blank ;
 Im not a payed member like many here, my considerations for that have not been established yet....

 Now having said that, I don't plan on dragging a bag behind my tool cart here, picking up all the ruffled feathers on the floor after posting. I'm not here to sugar coat things either,,,, nor spew uninformative information, waisting my time and others here.
I could find much better things to do with the limited time I do have.

I can say... Hey guys " Just keep doing what you been doing since its been working. Cool,

Now if I wanted to ask if anyone here would be accepting any RFQ's in the new year for smaller parts, up to say between 2- 50 parts per run, I'm not sure that your KISS approach would hit the numbers I'd be looking for.

Is their money in this type of work, I dunno, I haven't reached that level yet... obviously
Do I know what I'm talking about?
 Perhaps someday you will figure it out....

All the best Degen!
Eric


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## little ol' e (Nov 20, 2022)

My last post here,

I use mainly OSG carbide coated drills.
When I send them out for regrind ,
I request TIAlN coating upon return.

Why, I dunno... but it says it on the packaging when I receive them back.

Oh, haha, you know the best part... I think my wife loves these drills too. 
Cuz, she can walk around the place in some pretty nice clothing packin' an nice bag with the matching heals...


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## johnnielsen (Dec 2, 2022)

Susquatch said:


> Perfect John! Exactly what I have been after! Especially the versatility of turn, face, and plunge. I've liked off shore Trigons for turning and facing, but they won't plunge - at least not on my machine. If I could find a good tool and inserts that would be versatile, last long enough to be cost effective, forgiving of my many mistakes, and leave a decent finish behind that isn't embarrassing, I'd be a very happy camper. In fact, I'd even settle for a bad finish that needs cleaning up with another tool.
> 
> I don't suppose you have a recommended tool part number for them? Or do you think that is important?


Finally feeling well enough so went to the shop to identify my DNMG toolholder. Here are a couple of pics.


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## Susquatch (Dec 2, 2022)

johnnielsen said:


> Finally feeling well enough so went shop to identify my DNMG toolholder. Here are a couple of pics.



Thanks John.


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