Best Cutting Tools for Lathe Beginner

[kstrauss]

It may be an unpopular opinion but for a beginner I would put the HSS and brazed carbide into an inaccessible box (you might need a bit of HSS someday to grind a special trepanning cutter or something similar) and purchase appropriate insert tooling.

Do you have a grinder with guides or do you plan to grind freehand? How will you avoid ruining your diamond wheel when sharpening the brazed carbide?

As a beginner there is lots to learn so why add yet another new skill to the mix? Life is short; spend your time making stuff rather than attempting to learn tool grinding!

 

[Susquatch]

It may be an unpopular opinion but for a beginner I would put the HSS and brazed carbide into an inaccessible box (you might need a bit of HSS someday to grind a special trepanning cutter or something similar) and purchase appropriate insert tooling.

Please allow me the privilege of being the first to disagree.

My vote would be to put the brazed carbide and carbide inserts into a locked safe. Focus instead on using HSS. Learning to grind and hone HSS is a "learning" exercise. It builds basic skills and teaches us about how metal cuts, how to solve cutting problems, and about the geometry of successful cutting.

Do you have a grinder with guides or do you plan to grind freehand?

Make your own guides or grind freehand - both will contribute to learning.

How will you avoid ruining your diamond wheel when sharpening the brazed carbide?

Simple - the brazed carbide is in the locked cabinet beside the insert tooling. In my case, I more or less skipped over brazed carbide. Yes, I did use some, but I didn't sharpen it.

As a beginner there is lots to learn so why add yet another new skill to the mix? Life is short; spend your time making stuff rather than attempting to learn tool grinding!

This is the real meat of the debate. It's my perception that @CWret is a learner/innovator. I think the learning and understanding part is more important to him than simply making stuff.

For those who simply want to make stuff, I'd prolly agree but I'd put both HSS and brazed carbide in the locked box for them and simply tell them what carbide insert tooling to go and buy. I might also suggest they go CNC ASAP.

For those who enjoy the machining itself and the opportunity to learn and understand our machining hobby, I'd say start with HSS and a few carbide insert tools (for hogging out metal), throw the brazed carbide tools away or give them to someone who will use them, make some angle guides and a good adjustable grinding rest, and have fun. Grinding and using HSS is a shitload of fun riddled with learning opportunities that can be applied throughout our machining lives.

In my mind, it's a lot like handing gradeschool kids a calculator instead of teaching them basic math. It's all that the majority of them will ever need. But some of them benefit from understanding what they do and the calculator robs them of that learning opportunity. I think most hobby machinists are a very bright segment of the population and learning and understanding our hobby is actually the real hobby.

 

[Bandit]

Hmm, if I had to buy carbide inserts for every thing I did, I would be much poorer and would not get much done. As some inserts are over 10 buckos each, and 1 misdead may destroy the insert, verses a HSS bit that can be reground many times cause it could be 4 inches long, generly less then 10 buckos, and the fact 75% and more of my work is in unhardened metals, HSS is the go to.

 

[trlvn]

It may be an unpopular opinion but for a beginner I would put the HSS and brazed carbide into an inaccessible box (you might need a bit of HSS someday to grind a special trepanning cutter or something similar) and purchase appropriate insert tooling.

Do you have a grinder with guides or do you plan to grind freehand? How will you avoid ruining your diamond wheel when sharpening the brazed carbide?

As a beginner there is lots to learn so why add yet another new skill to the mix? Life is short; spend your time making stuff rather than attempting to learn tool grinding!

Hi Ken:

Just to offer an opposing experience...I find carbide inserts one of the most confusing subjects out there. A couple of time, I have spent considerable time reading and trying to decide what to purchase. Effectively, I've ended up with "analysis-paralysis" and never actually clicked the Buy button.

As I see it, carbide inserts are ideally suited for production work where an expert chooses the exact right combination of shape, grade, coating, etc, and then the lowly user can crank out parts with maximum efficiency on a heavy, rigid and powerful lathe. None of those key elements are present in my shop. (And cwret's Myford--while very nice--would not normally be described as "heavy, ... or rigid, ... or powerful".)

Re grinding your own high speed steel, I found a clear, concise web page that, for me, helped demystify what to do and why:

Tool Grinding

Tool grinding

www.steves-workshop.co.uk

There are only three surfaces to grind and the cutting corner needs a radius. That's it!

The beauty is that if you don't like the result, you can grind away any evidence of your first attempt! (With carbide inserts, you'll have 9 more inserts in the package looking askew at you every time you open that drawer. But you won't be able to bring yourself to throw them out because 'they might work in some other situation'.) Each stick of HSS comes from the factory with 2 (two) ends just begging to be experimented upon!

Craig

 

[Susquatch]

A couple of time, I have spent considerable time reading and trying to decide what to purchase. Effectively, I've ended up with "analysis-paralysis" and never actually clicked the Buy button.

Wow, does that ever resonate with me! In my case "considerable time" was several years.

I kept reading how wonderful and how efficient carbide inserts are. Then some machinist would talk about advice he got from the manufacturer, and my eyes would glaze over. No way some expert would waste his time educating some hobbiest like me who might buy 2 inserts per year.... Not gunna happen.

Surface treatment, target metallurgy, nose size, anvil application, tool holder specific, etc etc all just complicated the rat shit out of buying, Then I hit the rhomboid vs Trigon vs triangle vs round debacle. Everyone had their favorites. They were ALL the very best shape. At $$$ per insert, I kept chickening out.

In desperation, I bought a kit of 7 tools and a kit of replacement inserts for them for different metals. What a waste of money that was! I tried them all but almost always ended up going back to HSS to get the real work done.

On the plus side, I did come to believe (rightly or wrongly) that Trigon inserts were a reasonable compromise of life expectancy and range of application, and that a round insert left a decent finish more often than other insert shapes.

A few years later I felt comfy enough to buy a few dedicated holders that came with a box of inserts for each insert holder for steel. One rhomboid, one triangle, and one Trigon. If I had to do it over, I'd only get a left and a right Trigon tool. The others gather dust. All they really did was confirm my earlier thinking on why Trigon was better for ME.

For now, I'm still loving HSS, using the Trigon carbide insert tool for roughing, and bought a few packages of inserts for aluminium for better finishes and finer cuts.

After 8 years I've only just now developed the confidence to buy some carbide threading inserts and tools. (They are the ones I brought to the meetup to ask @thestelster about.)

Ya, I resonate with your comments Craig. So very true.

 

[trevj]

Hmm, if I had to buy carbide inserts for every thing I did, I would be much poorer and would not get much done. As some inserts are over 10 buckos each, and 1 misdead may destroy the insert, verses a HSS bit that can be reground many times cause it could be 4 inches long, generly less then 10 buckos, and the fact 75% and more of my work is in unhardened metals, HSS is the go to.

Likewise, HSS rocks, and you will NEVER be stuck in a corner waiting for someone else to make or send you that 'perfect' tool for a particular job. Carbide has it's place, but for the dollar spent, you don't get very many chances to screw up, even on the 'tougher' grades and edge profiles of insert.


Personally, I prefer the 1/4 inch square tools, though the 3/8 x 1/2 rectangular section are really handy for boring bars and internal threading tools. I use the ones that go on sale for 1-2-3 bucks apiece, and buy lots each time I need.

Carbide looks like the answer, until you are on your last of a package of $80 or so dollars worth, in a day's adventures, and you still cannot figure out why nothing is working. Watched it play out dozens of times with some of the dudes I taught. And I say dudes, because inevitably, every female tech that came through the shop read the directions they were given, and followed them, instead of trying to be smarter than the training syllabus!

Despite what a carbide insert WILL tolerate, a LOT of the newbie motions and movements on a lathe, simply destroy the cutting edges before they ever get put to work, much of the time it is simply bumping the tip against the work while attempting to touch off without the lathe spinning at speed appropriate for carbide, which plays holy hells with the tips or edges. Same with panic stopping the lathe with the tool in the work, the tiny little bit of reverse movement that generates as the lathe stops with a cutting load on the tool, will make your insert's edge vanish like yesterdays time!

 

[kstrauss]

It's great to see some thoughtful discussion and I suppose that I'll stick my neck out even further.

I mostly turn aluminum (6061) and plastic (Delrin and some UHMW) with occasional items of 12L14 or 1144 steels. I often need short but accurate internal bores for bearings and long bores for housings and such. Also, internal threads. For my projects, polished positive rake inserts such a DCGT and CCGT work well. I've had excellent results from the cheap eBay Chinese inserts labled as "Iscar" but almost certainly not. Prices have recently greatly increased but most of my inventory (probably sufficient for my lifetime) was purchased for less than $20/box of 10 and each insert has 4 edges so $0.50 per edge. Prices on eBay are now double or so ($1/edge). I don't think that it is reasonable to save a dollar by using HSS but then to waste 15 minutes sharpening plus having to reset tool height; your mileage may vary!

For boring I use Chinese solid carbide boring bars with CCGT inserts. The carbide boring bars are more rigid than steel ones and that is essential for a 1/2-inch bore 3 inches long. I'm uncertain how one would substitute HSS. Plus, I can use the same insert for both inside and outside turning.

I agree that a bump knurler is not really suitable for a light lathe such as a Myford. Hemingway Kits have a rather nice scissor type that is specifically Myford sized. Or maybe a cut knurler would be a good project.

 

[gerritv]

I'm in Ken's camp 100%. My goto store: https://www.aliexpress.com/store/911783152 You can infer the brand for the intentionally mislabelled headings. Most (all?) of these packages have the DIN colour codes along with cutting parameters on them.
Compared to no-name labelled ones that I used to buy from AliExpress I am inclined to believe the branding. I am guessing that the huge volumes these are bought for factories there that the price plummets accordingly. And for hobby use it really doesn't matter in the end anyway.

At the risk of being repetetive, this is the goto site to decipher the cutting nifo .e.g. VPTF or PC9030. https://www.machiningdoctor.com/grades/ as further confirmation of brand and parameters. And remember that your DOC is best kept to the tip radius as a minimum for carbide.

HSS would still be useful for form tools of course.

gerrit

 

[JustaDB]

For boring I use Chinese solid carbide boring bars with CCGT inserts. The carbide boring bars are more rigid than steel ones and that is essential for a 1/2-inch bore 3 inches long. I'm uncertain how one would substitute HSS. Plus, I can use the same insert for both inside and outside turning.

I'm an HSS bit kinda guy for outside & face. Todate I have not done any boring, but yours is the approach I have decided upon for a couple projects waiting in the wings..

 

[CWret]

understanding our hobby is actually the real hobby.

Yes in spades.

 

[trlvn]

@kstrauss what lathe are you using?

@gerritv You've got effectively the same lathe as me so I could be talked into following your footsteps, exactly. Precisely. Even blindly. If you can point me to a particular package of inserts and related insert tool holder for basic turning in mild steel, I'd be very grateful. (I take it these general handle light facing cuts as well?) My goal is mainly to making roughing faster since carbide can take/wants much higher RPM's and will therefore finish passes faster.

I'd also be interested in a carbide insert system for _small_ diameter boring. Say starting with a 1/2" hole, give or take?

Craig

 

[trevj]

It's great to see some thoughtful discussion and I suppose that I'll stick my neck out even further.

I mostly turn aluminum (6061) and plastic (Delrin and some UHMW) with occasional items of 12L14 or 1144 steels. I often need short but accurate internal bores for bearings and long bores for housings and such. Also, internal threads. For my projects, polished positive rake inserts such a DCGT and CCGT work well. I've had excellent results from the cheap eBay Chinese inserts labled as "Iscar" but almost certainly not. Prices have recently greatly increased but most of my inventory (probably sufficient for my lifetime) was purchased for less than $20/box of 10 and each insert has 4 edges so $0.50 per edge. Prices on eBay are now double or so ($1/edge). I don't think that it is reasonable to save a dollar by using HSS but then to waste 15 minutes sharpening plus having to reset tool height; your mileage may vary!

For boring I use Chinese solid carbide boring bars with CCGT inserts. The carbide boring bars are more rigid than steel ones and that is essential for a 1/2-inch bore 3 inches long. I'm uncertain how one would substitute HSS. Plus, I can use the same insert for both inside and outside turning.

I agree that a bump knurler is not really suitable for a light lathe such as a Myford. Hemingway Kits have a rather nice scissor type that is specifically Myford sized. Or maybe a cut knurler would be a good project.

Yeah, I like the xxGT inserts for those uses. Other than the number of times I forget how sharp the frikken things are, and slash myself on them... Slow learner, according to the scars! LOL! They are, however, far more susceptible to rookie mistakes, as that sharp edge is really fragile if the wrong pressure is applied.
The xxMG inserts, are pretty all-round performers in mild steels too.

I'll profess to being about the LAST guy on the planet to tell you to avoid carbide altogether. But I really do suggest that you learn to make the best out of HSS tooling first, so you become very comfortable with using the lathe, and understanding how things can and do go wrong.

But mainly, because HSS bits are cheap as chips, and you are never without options, provided you are comfortable grinding, and understand how to shape various tools. You never chip the 'last' HSS edge and end up stuck!

 

[trevj]

@kstrauss what lathe are you using?

@gerritv You've got effectively the same lathe as me so I could be talked into following your footsteps, exactly. Precisely. Even blindly. If you can point me to a particular package of inserts and related insert tool holder for basic turning in mild steel, I'd be very grateful. (I take it these general handle light facing cuts as well?) My goal is mainly to making roughing faster since carbide can take/wants much higher RPM's and will therefore finish passes faster.

I'd also be interested in a carbide insert system for _small_ diameter boring. Say starting with a 1/2" hole, give or take?

Craig

KMS sells the TMX lines, which are sorta a better grade of cheap import, and they have bars down into that range.

I brought in to work a insert boring bar that would do a 3/16 inch hole. The inserts were pretty tiny. Had to make a mounting block to adapt it to the QCTP on our best lathe.
We blew up several of the boring bars, before we realized that hand feeding bars that small was a nightmare. You HAD to set a very fine power feed and rely on it to keep the loads even!
One twitch of an over caffeinated hand was death to the insert or the bar and the insert.

We finished THAT job with hand ground HSS boring bars from the same stuff we made all the other lathe tools from, FWIW...

From a hobby perspective, there is a LOT to be said, for drilling, then boring the hole undersize, before applying a suitably sized machine reamer to it. For that matter, there is at least as much to said for that professionally!

 

[gerritv]

@trlvn you should visit
I think these are all available from the store posted above. If not, any store on AliExpress will do for these holders. My go to is an SCLCR1010 that uses CCMT060204/08 inserts. Facing and regular cutting.
I more recently added an SVJCR1212 and SDJCR1212 (12mm only because I got them free, 10mm would have been fine height-wise.) These use VCMT110304/08 and DCMT070208 inserts.

My boring bars are all SxxK using CCMT0602 inserts. xx is various size, I think my smallest is 6mm. Those bars you can oftn find in a set of 4 or 6 afaicr . CMT inserts are DiaEdge/Mitsubishi or Sandvik. Again, from DOT Strip store linked above.

gerrit

 

[trevj]

I'm in Ken's camp 100%. My goto store: https://www.aliexpress.com/store/911783152 You can infer the brand for the intentionally mislabelled headings. Most (all?) of these packages have the DIN colour codes along with cutting parameters on them.
Compared to no-name labelled ones that I used to buy from AliExpress I am inclined to believe the branding. I am guessing that the huge volumes these are bought for factories there that the price plummets accordingly. And for hobby use it really doesn't matter in the end anyway.

At the risk of being repetetive, this is the goto site to decipher the cutting nifo .e.g. VPTF or PC9030. https://www.machiningdoctor.com/grades/ as further confirmation of brand and parameters. And remember that your DOC is best kept to the tip radius as a minimum for carbide.

HSS would still be useful for form tools of course.

gerrit

Your GoTo store tries to talk to me in a language I don't understand, and refuses to let me in past the 70 percent whatever the offer is...

And yeah, a CCMT or DCMT edge is probably among the cheapest and most available carbide inserts out there!

Edit: Jeebus! Whoever programmed that site needs to be drowned in a bucket of something resembling sewage!

So, aside from deciding I needed to be catered to in french, you need to exit out of the 'offer', at which time another 'offer pops up, that you need to choose the "Quitter" option, instead of simply hitting the "X" to (you hoped!) close the pop-up... <spit> And I had to go through the language selection process twice before it actually gave me English...

 

[gerritv]

if the language/currency is off English/Canadian then change it at top right of page. I have never figured out the madness behind how they set this, it seems random even when logged in.:-(
And there will be a subtle X to click to get past the offer of the day. Usually top right of the image

 

[trevj]

if the language/currency is off English/Canadian then change it at top right of page. I have never figured out the madness behind how they set this, it seems random even when logged in.:-(
And there will be a subtle X to click to get past the offer of the day. Usually top right of the image

Yeah, see edit to prior post. Aside from having to battle the pop-up, gotta say the stuff actually 'looks' a step up from the low rent import stuff!

 

[kstrauss]

@kstrauss what lathe are you using?

@gerritv You've got effectively the same lathe as me so I could be talked into following your footsteps, exactly. Precisely. Even blindly. If you can point me to a particular package of inserts and related insert tool holder for basic turning in mild steel, I'd be very grateful. (I take it these general handle light facing cuts as well?) My goal is mainly to making roughing faster since carbide can take/wants much higher RPM's and will therefore finish passes faster.

I'd also be interested in a carbide insert system for _small_ diameter boring. Say starting with a 1/2" hole, give or take?

Craig

I have a Myford S7b (1985 vintage green and bought about 20 years ago). I've updated with a 1/2-hp 3 phase motor + VFD.

For smaller bores I would suggest a 6mm (SCLCR06) solid carbide bar. This will handle an 8-mm bore. Look for something like https://www.ebay.ca/itm/145457026982 (I have no knowledge of this vendor or the quality of their products.) A SCLR08 (8mm) bar is much more rigid than a 6mm bar and good to have for slightly larger bores. I have 6, 8 and 10 mm solid carbide boring bars.

 

[kstrauss]

KMS sells the TMX lines, which are sorta a better grade of cheap import, and they have bars down into that range.

I brought in to work a insert boring bar that would do a 3/16 inch hole. The inserts were pretty tiny. Had to make a mounting block to adapt it to the QCTP on our best lathe.
We blew up several of the boring bars, before we realized that hand feeding bars that small was a nightmare. You HAD to set a very fine power feed and rely on it to keep the loads even!
One twitch of an over caffeinated hand was death to the insert or the bar and the insert.

We finished THAT job with hand ground HSS boring bars from the same stuff we made all the other lathe tools from, FWIW...

From a hobby perspective, there is a LOT to be said, for drilling, then boring the hole undersize, before applying a suitably sized machine reamer to it. For that matter, there is at least as much to said for that professionally!

Many of my holders are Glanze branded 10mm shank holders from https://www.chronos.ltd.uk/ Probably not the cheapest or the best value but decent quality.

 

[trevj]

Many of my holders are Glanze branded 10mm shank holders from https://www.chronos.ltd.uk/ Probably not the cheapest or the best value but decent quality.

I have dealt with numerous eBay sellers out of the UK, and postage seemed cheaper and faster than Canada Post!

It's a tiny little world, these days!