What inserts do you like and why?

[thestelster]

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.

 

[thestelster]

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

 

[thestelster]

Parting on the lathe: carbide inserts.

 

[Susquatch]

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......

 

[LenVW]

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

 

[Susquatch]

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?

 

[thestelster]

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.

 

[Dabbler]

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...

 

[thestelster]

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]

@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.

 

[Tecnico]

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.

 

[Dabbler]

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.

 

[thestelster]

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.

@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.

 

[DavidR8]

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......

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

 

[VicHobbyGuy]

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.

 

[VicHobbyGuy]

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.

 

[Dabbler]

@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]

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.

 

[VicHobbyGuy]

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)?

 

[DPittman]

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.