Machining carbide?!

Some testcuts with a cbn insert in tungsten carbide.
Common knowledge is that diamond coated tooling is used to machine tungsten carbide, but goes to show, even the softer CBN can cut the sintered carbide.
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[@matman7546]

The cobalt matrix is the source of the ferromagnetic properties. Cobalt itself is ferromagnetic. Cubic boron nitride is much harder than even pure tungsten carbide, with cubic boron nitride and tungsten carbide coming in at ~5000 and ~2000 knoop hardness, respectively. Diamond is ~7000 knoop hardness and the average m2 hss toolbit is ~750 knoop hardness, for reference.

[@zumbazumba1]

First time i hear for knoop hardness.I heard for brinell ,vickers ,rockwell but firs time for knoop.

[@Ujeb08]

@@zumbazumba1 Knoop Hardness testing is with the tip of a tiny diamond. It's used for testing very thin coatings and materials. Also can be used in very small areas where you do not want indentations that are easily visible to the naked eye. I used to demo the work hardening of 1/8" thick bent aluminum on the neutral plane and tensile and compression areas around the profile of the bend

[@zumbazumba1]

@@Ujeb08 so its something similar to rockwell testing machine but with smaller force.You learn something every day!

[@mtcru]

@@Ujeb08 this is solid carbide all through, so do you have an idea why he mentioned knoop hardness here?

[@simonhopkins3867]

Interesting. Thanks for the perspective.

[@CatNolara]

The magnetism stems from the cobalt matrix. Tungsten carbide is sintered together with some percent cobalt to fill any voids. That's also why you shouldn't breath that stuff in, because the cobalt creates toxic and carzinogen compounds. This could also explain the pitting of the surface. Anyway, very interesting video. I wondered for a while now which would win, carbide or CBN.

[@trollmcclure1884]

cobalt creates toxic and carzinogen compounds? Like Vitamin B12? Where does it come from? It's a trace mineral. Good for bones creating red blood cells.

[@sydneyshinshi]

Is that a german joke I hear "my wooden poker here is very big"

[@michaelguzzi1]

Sure is possible, especially the "ultra special carbide" my boss buys, which BENDS... lol

[@ferrumignis]

Ahh, Chinesium Carbide

[@danjennings5068]

Ah yeah. I've had some of those. Strangely light for carbide too.

[@fizzleshizzle8314]

@@danjennings5068 could you please share the brand name or link to the product? I really appreciate it in advance!

[@fizzleshizzle8314]

Where could I get those carbides? Please share brand name or links. Really appreciate it!

[@danjennings5068]

@@fizzleshizzle8314 no idea, it was >decade ago.

[@troyprideaux8768]

I really appreciated this video, especially the tip on how abrasive the dust/shavings can be on the chuck and ways. Also appreciated the analysis on wear and cuts.

[@lancer2204]

Very interesting Stefan. I think the swarf from the turning could make a coarse lapping compound with the addition of some suitable oil. 😉

[@YulehHabibi]

6:30 "ah its hot" I'm glad your reflexes are also in English ;)

[@RRINTHESHOP]

Well done, very interesting. Thank you for experimenting for everyone.

[@StefanGotteswinter]

Thanks Randy!

[@shawnlund]

I learn something from every video you make Stefan and enjoy the hell of out em.

[@literoadie3502]

Very impressive! So nice to know that materials like carbide and CBN are easily available to machinists. A bit of diamond grinding and you've got yourself some amazing tools!

[@willi-fg2dh]

call it Wolfram Carbide . . . it's geekier!

[@jtkilroy]

I have never seen carbide turned in such a manner. Could you do a comparison to a PCD insert? I know there is a significant price bump for good PCD inserts, but it would be an interesting comparison.

[@bulldozer7656]

Wow, I never thought that was possible. I use CBN on inconel w good results and diamond polish for final.. Thanks Stefan!!

[@TomMakeHere]

That's some hard hard turning! So machining CBN next? That's really cool. Thanks for sharing

[@tyhuffman5447]

Ok man, I have watched every episode you have released except for the ones related to the 1911. I live in the US I can buy a 1911 on the way to the liquor store. No need for a 1911 replica.Your camera work has improved a lot, your video equipment has improved as well, your ability to tell a story with your videos has improved as well. Your machining and the shop has improved greatly. Here's to the next 9 years. Cheers!

[@bostedtap8399]

Excellent Stefan, always learning Sir, the "Micro-grain" sintered materials are very impressive under high magnification ( X500 plus), for sintered steels, they are advertised as clean, ref near zero tramp elements, and giving higher mechanical strength. Cast steels (all steels are cast), have many undesirable elements, eg Antimony, Boron, Copper etc, elements are added, such as Calcium is added to remove impurities; quite an art to steel making!. Obviously sintered materials do not have a grain direction, so no uni-directional strength, such has a lever/pry bar. Many thanks for sharing.

[@SteveSummers]

Thanks Stefan. I enjoyed the demonstration. I wouldn't have though to try it.

[@Xraller]

Me: You can’t machine carbide Stephan: Hold my beer....

[@captcarlos]

Ahhhh a Binky reference. Sweet.

[@doubledarefan]

Germans do not drink beer, they drink Bier.

[@benwinter2420]

Gets angle grinder out

[@lifuranph.d.9440]

@@doubledarefan Ya!

[@andreturnbull1259]

Very interest test and results. I wondered if the geometry of the insert (rack angle etc.) would have much effect on the life of the tool and the finish? Perhaps you could do some further tests with different cutting angles? I really do enjoy your videos, as I learn something from every one of them. Thanks Stefan for taking the time to make video.

[@flaplaya]

The reason most people don't machine Sintered WC-Co/WC-Ni-Fe is due to the very toxic dust. I learned this after getting a very bad respiratory illness after grinding some inserts with a diamond blade.. Not as bad as grinding Beryllium compounds but still pretty bad.

[@thatdrillguy7889]

There's a difference between what is possible and what is efficient or productive. It makes sense that you can turn cemented tungsten carbide like this especially when you think of grinding as just cutting with a MANY fluted diamond tipped tool for example. In fact, some hard molds/dies (hardened steel, clad, or carbide) are machined with solid carbide ball endmills. These are VERY special tools, but carbide nonetheless. Using a full sharp pCBN insert like the start of this video is far from ideal, let alone the work holding, tool holding and machine stability, but it works of course. Good experiment and nice video.

[@kennethjanczak4900]

Thanks for taking the time to make the video and share it

[@tmurray1972]

Give a man a CBN insert and a small lathe and he can move the world...lol.👌👊🏻 Wish we could see the drilling and threading, that must be pretty cool.

[@jaapweel1]

Way back when I was an intern in a physics lab, I was tasked with grinding holes in big chunks of glass using silicon carbide powder. The machine shop guys refused to let that stuff even enter their shop. I ended up using an old drill press in a hallway in a subbasement as far away as possible from the machine shop... But I remember the faces of the machinists when I mentioned using that stuff anywhere near a machine tool, even an old drill press 😜

[@crabmansteve6844]

Carbide is going to look like it has a porous, pitted surface finish because it's been sintered. Usually liquid phase sintering in carbide's case. It's packed, and heated until it melts about 15% and the capillary action pulls the now melted product in and fills the voids. It's really really cool.

[@turningpoint6643]

Definitely chips and most impressive Stefan. You'd certainly know more than I would and this is just some semi logical guessing. Because of the sintering process that pitting in the turned surface at 40 X magnification makes sense. My guess is those are areas where individual grains of carbide are being ripped out of the surface of the cobalt binder. A lot of heat was going into the end mills shank and not into the chip. That might not be a bad thing as from what I understand carbide at the correct feeds and speeds can help to plasticize the material being cut because of the very high frictional heat and tool pressures right at the cutting edge. That CBN might be doing the same thing to the cobalt binder? The CBN might be doing most of the cutting on the cobalt and that's what's helping to remove the carbide? Because of the two different depths of cut it's hard to say how much cutting edge damage is being done with your first 10 passes and the lighter depths of cut verses the one heavier cut. One light depth of cut and then an inspection under your microscope might reveal more about how the damage is getting started. Then further passes with the same depths of cut with a microscope inspection after each one. I also suspect some impact erosion of the CBN due to the hard carbide particles hitting the even harder CBN at high speed might also part of the problem (maybe). The cutting edge looks like it was destroyed mostly because the forces were higher than the cutting edge material could withstand and the material broke apart. The initial damage was then enough to start the material to fracture deeper into and away from the maximum cutting pressure point. The fracturing isn't showing the pattern one would think would happen with the force vectors that should be happening. But maybe that's usual with something that hard? The light squealing noise was a sure indicator of chatter so it's possible that did most of the damage once it started than the heavier cut did? As you pointed out those rough grinding lines causing stress risers wouldn't have helped with the cutting edge life once the edge started to degrade. As always a very interesting video, but it may have raised more questions about what's happening at the tool edge than it answered. :-) It's quite probable at ultra high magnification like an electron microscope could give might show a great deal more with those chips and how there being formed. Even though the CBN is harder than the carbide, is the carbide actually being cut or is it mostly the binder being removed that's taking the carbide with it? It would be great if one of your viewers did have access to that type of microscope and could provide high resolution pictures of those chips. I could also be 100% wrong with anything I've said since it's only rough guessing at best. Your seriously insulting that lovely Super 11 by calling it only a hobby level lathe. I've never seen Emco call it anything other than a light industrial or tool room lathe in any of there advertising. :-)

[@feedthefreak2139]

I used to machine a lot of carbide on CNC lathes some years ago, making dies for cold forming machines. The same way you are doing, with CBN inserts. It was more cost-effective than EDM.

[@thefixerofbrokenstuff]

Wow, I wouldnt want to be within a half mile of those chips. Looks like something that would get inhaled clear into your prostate. You better switch to filtered Pall Mall's. Interesting video none the less, thanks for posting.

[@bobuk5722]

Interesting bit of R&D Stefan, and very well presented as usual. Thank you for all the work you put in to making these videos. BobUK.

[@Toolman22364]

Pretty cool Sir . Need to get you a shirt with the Big S on it . Super Stefan. Awsome video Sir

[@willmcgo8288]

What did I learn? I learned that I'm not going to try and cut my own carbide taps from old end mills. Thanks for the lesson!

[@firstmkb]

Always interesting, thanks. Now I want a CBN kitchen knife that I'll never need to sharpen!

[@letsgoBrandon204]

Unless you cut carbide with it ;)

[@firstmkb]

@@letsgoBrandon204 that would make a memorable Tuna Surprise!

[@MattysWorkshop]

Very interesting, thank you for taking the time to show it can be done, thanks Stefan, ATB Matty

[@janeinarwold2663]

Finally! two weeks is hard for an addict like me. Thank you! Btw: Is the magnetism we see really magnetism? Maybe it`s static electriticity?

[@PSUQDPICHQIEIWC]

The material contains cobalt, which is a ferromagnetic metal.

[@DudleyToolwright]

Interesting. I would not have guessed. You never fail to entertain.

[@zvonibab]

wow something new learnt every day Thank you Stefan!

[@MakinSumthinFromNuthin]

I learned I need better tooling! 😊 Excellent experiment! ~ Richard

[@glennstasse5698]

Thanks as always for the video. I always learn a lot by watching and the comments often add more good info so the channel is always great. The comments convinced me to steer clear of any thought I may have of sharpening any of my carbide tools. (Router bits, etc.) I bet cleaning the chuck afterward is a fun job!

[@chuckthebull]

I have to cut down a carbide end mill to fit a certain cutting job and i was unsure if it was even possible ,,,so thanks for this video i think ill give that a try and see how i do...cheers

[@narendrabogavelli7648]

Good experiment ,thankyou.Really enjoyed it.

[@Ricardo6784]

Great Video. Thank you for taking time to show us.

[@sridharbabu32]

thank you for the video - great information - great job 🙂

[@bobvines00]

Stefan, will you be regrinding the CBN insert with a "finer" diamond wheel? That way you can see how much longer the insert could last. This was a very interesting video!

[@StefanGotteswinter]

I definetly will regrind it, but until i have a proper need for it, I will not do much additional experimentation on this - First I want to learn more about it and get some proper tooling for it.

[@burntorangeak]

Yup. I only huff carbide dust on the weekends.

[@HanstheTraffer]

We ALWAYS LEARN from your videos....mostly learn to "think outside of the box" and try different things.

[@scotty362100]

You really know how to DESTROY ones ego! To think I still struggle with turning/getting a good finish, mild steel! lmao

[@marvincallaway1325]

Good video Stefan but I wouldn't have believed it if I hadn't seen it. Now I know it can be done.

[@petersmith5277]

I did learn- it took me into better understanding of micro processing and one wonders if you had a mask on in view of micro chip dust. Thanks for excellent demo.

[@StefanGotteswinter]

Dräger X-plore 3500

[@OstapHelDesigns]

Interesting as always, well done!

[@alfredlyon27]

Interesting but it begs the question, why? Faster and more efficient to just grind it . I get asked the question all of the time and I them exactly what you did. Get yourself a cbn or diamond insert and go for it. I also tell them to buy a used KO Lee on eBay and a couple of diamond wheels.

[@StefanGotteswinter]

Fully Agree for turning just straigt diameters/steps or necking down endmills, grinding makes more sense for those applications. I think it could be interesting if a shop had to do complicated shapes in carbide. Cnc lathes are a bit more common for a general shop than a cnc cylindrical or cnc t&c grinder. Granted, very limited usecase. Also agree that every shop needs at least one manual grinder of some sort ;) (Milling and drilling carbide is in my oppinion more viable, we try to replace a lot of sinker-edm work with it) Thanks for watching, Alfred, I feel honored to have you watch.

[@alfredlyon27]

Stefan Gotteswinter Thank You for the reply. I really enjoy your videos. The quality of sound and camera set up is wonderful. I agree, in a perfect world every shop would have everything they need but sometimes you have to do whatever works.

[@drmadge]

Stefan, as always super interesting; thankyou. Having seen this, I'd love to learn more about the threading/drilling for custom tools with high Youngs' modulus. I'd not have thought it possible to do in the home workshop. Thanks again, I salute you.

[@wdcjunk]

"Ah it's hot!" I lol'd at that

[@alexbarnett8541]

I knew you could do it. Have a good time cleaning your Six Jaw chuck!! Great video thanks.

[@CRUZER1800]

I always enjoy your videos, Stefan. This one is pretty cool... Thanks for sharing.

[@rudebwoyyyy]

Bin schwer beeindruckt vielen Dank für die Beweisführung

[@stumccabe]

Thanks Stefan - I learned something new!

[@jameswyatt1304]

So basically every cut will be like a "finishing" cut... Interesting video in an interesting series.

[@rickmyers3716]

Learning plenty from this vid-It inspired many questions! Now I’m wondering what affects would be noticed with coolant or lubrication... perhaps you’ve opened a can of worms lol. Love your videos, man! Yours, RobRenz, & Tom Lipton = my KZbin addiction.

[@StefanGotteswinter]

Cooleant/lubrication would probably cause serious problems. All the carbide cutting tools I have seen so far want to be run dry, with airblast to clear the chips.

[@jay7605]

Very interesting watch. Thanks Stefan.

[@davestambaugh7282]

Amazing I do know that if you try to grind carbide with a CBN wheel, the wheel will be instantly left un usable. It is traditionally said that if you grind steel with a diamond wheel it will instantly kill the wheel. I have found this not to be true. The B&S drill doctor has a diamond wheel so that you can sharpen steel drills yet still grind carbide masonry drills. If the wheel was CBN you could not grind the carbide. CBN wheels were not really necissary intil they came out with the fifteen percent cobalt HSS which you will find is next to impossible to grind with aluminum oxide wheels.

[@PhaseConverterampV]

Impressive Stefan

[@CraigsWorkshop]

Interesting stuff Stefan. I wouldn't have even thought to try it (and I don't own any CBN inserts), but this tip is now filed away for some future time. I will make sure to wear my dust mask too! Cheers, Craig

[@agapiosagapiou]

Thank you for sharing with us! Is good to know!

[@TeslaAtoms]

Now i would like someone to machine carbide on a cnc mill.

[@mpetersen6]

Three words. Rigidity, rigidity, rigidity. Anything moves, any chatter the insert is toast. I always liked using CBN for hard turning. Glass smooth finish with very little heat going into the work.

[@waldemarii]

If you ever visit finland I will leave some cbn tool bits and beer around my mb4 so you can tram the z-axis.

[@lohikarhu734]

It seems that a vacuum pickup at the tool would control some of the chips, as their mass is so low... also, do you have any idea if any kind of fluid could be used to either lubricate, or cool, the cutting process? Grüße aus Schwaben...

[@StefanGotteswinter]

Yes, I would definetly run dust extraction if I had to do this for real. The carbide milling we do is done completely dry, just with air - I guess that would be the same for turning too.

[@Paul-pl4vy]

Cbn is full depth. Loads of power

[@GastonSWE]

Looking forward to the video on milling with small diameter end mills on slow machines ! (At least I am hoping for one ;) )

[@xenonram]

He did a video about how there is no place for HSS in a machine shop anymore. He went into using small ¼" carbide EMs, rather than HSS EMa, even on slow/hobby machines. I forget what video it is. It is possibly one of the "shop talk" videos because I couldn't find it.

[@StefanGotteswinter]

Yes, still collecting footage for that - I dont want to show only testcuts for that video, but realworld machining ;)

[@GastonSWE]

@@StefanGotteswinter Take your time, I'm sure it will be a very interesting and useful video! I'm not asking or suggesting, but It would be a plus if the video covered some gummy materials and some examples of machine behavior numerics that would make this impossible (like max stick slip motion and limited resolution of steps on CNC).

[@TheEdguitars]

Would be nice to see the miniature 1911 project back some day :)

[@billsmith5166]

He can't. I think Germany considered it a weapon. He talks about it a bit in one of his Q and As.

[@SharkyMoto]

i think adding a flood cooling would greatly improve the tools life and reduce the amount if carbide getting airborne? not an expert by any means, but lubrication was always good for the stuff i did, especially if machining hardened stuff

[@pit7794]

Hi, pls. try CVD diamond edge for the next time, 3x harder than CBN and the apropriate material to cut tungsten carbide both in turning and milling operations as well ...

[@lwilton]

I'd be inclined to say those chips look like spalling artifacts more than continuously peeled chips. Which just says they are chips out of a composite material.

[@robertfenney]

great video!

[@Smallathe]

Thanks for sharing!!!

[@TomChame]

Very interesting, I liked. Also learned to not try it at home. :)

[@woodscreekworkshop9939]

Very interesting, thanks for sharing 👍🏼

[@PatriotCoinRings]

Rookie question: Would it have helped to keep the bar lubed with cutting oil or the workpiece cooled by spraying or running water periodically on it?

[@matttradie1341]

Interesting that the surface is chipped on the original surface, but not chipped where you took a deeper cut and backed out on the turned finish. Perhaps it has to do with the ground finish?

[@bobengelhardt856]

Maybe it was the heavier cut at the end that chipped the insert. And continued cutting with the smaller DOC would have been fine.

[@Pest789]

Inb4 Adam and Keith each do a 'chip control' lathe duel trying to max out DOC and feed rate machining carbide

[@nandayo00]

It's a very impressive video. I wonder the angle of breaker, CBN insert.

[@youcoulduseit7492]

Ya that was intresting. holding the part in a collet thats closer to the spindle baring would reduce deflection and might make that insert last a bit longer. the collet strategy would be easy to machine 12mmm pull it out of the collet another 12mm if the part is long. seen those inserts on ebay for like $7-8 I'd have to wear it on a necklace so i dont lose it in my messy shop though

[@multiHappyHacker]

You can cnc mill custom HSS form tools too.

[@OldtimeIronman]

Wow I did not know this was possible, thanks!

[@edgeeffect]

"hey maaan, you can't turn carbide on a hobby machine" :D :D :D :D :D :D

[@stefantrethan]

The sound reminds me of the time I accidentally faced some glass tubing because I thought it was plastic. Only that was probably quite a bit softer....

[@bigbird2100]

Stefan maybe use a used diamond tool and try to use it as a Burnish tool Cogsdill do a nice line in Great video.

[@benwinter2420]

Those old Australian Sutton tools 'coated' end mills were garbage , the coating chipped off of the edges near straight away & went blunt , have Dormer HSS end mills that are still sharp

[@victoryfirst2878]

Hello Stephan, I have a small atlas super precision lathe with timken roller bearings in the headstock. I have machined carbide to .0005 total tolerance on a regular basis. I was just doing some "Can I Make It Happen Stuff" which you call R and D. You said you have a high end German machine, what is the name and model ??? When I machined the carbide I used collets as it is easier to keep the dust under control. All I did was machine a 1/2 inch diameter which is 12.7 MM. Also, I agree with you on the machined metal as chips, the limes (English)call it swarf. I will agree with you Stefan that the chips do look like cast iron. But the dust is not good for you for sure. Good day to you Sir.

[@incubatork]

I suppose a lot depends on the hardness of the mill to start with, some of those chinatown mills are not so hard(going by how long they last) compared to a decent end mill

[@MorRobots]

Interesting..... Shank reduction for running larger end-mills in smaller collects in a small shop setting?

[@davestambaugh7282]

I am retired now but I always machined my carbide parts before it is sintered it is far easier that way.

[@jhbonarius]

And how do you machine diamond coated tooling or CBN? I'm not hearing a vacuum... you don't mind the carbide dust?

[@StefanGotteswinter]

For the video I was wearing a dust mask - If I had to do this for real, I would add dust extraction. The diamond coating gets added after the carbide base material is ground/sintered into shape. CBN can be ground with a diamond wheel.

[@spamspammesen5970]

​@@StefanGotteswinter PCD (poly crystaline diamond) coatings are "ground" with EDM "grinders". I learned this from our tooling provider when discussing them making a custom diamond tool for us. They told me this is basically a normal tool grinder with a copper wheel, attached to an EDM generator and submerged in fluid like normal EDM. They also told us that they didn't have this kind of machine, but are using normal wire EDM when they are makind custom tools like the one they were making for us. This was tools for the woodworking industry. Diamond tools are the only kind of tool you get decent tool life out of when machining MDF. But I expext the process to be possible to use for metal working tools as well.

[@Skironxd]

@@spamspammesen5970 Very interesting that diamond tools are the only kind you get decent tool life out of when machining MDF. Why is that?

[@samrodian919]

Very Interesting Stephan, i wonder if you were to regrind the insert and then hone it with a much finer diamond hone, do you think you could get a greater amount of work before it broke down again?No doubt you have cleaned up your lathe very well already so are not inclined to do it again but the thought is out there!

[@davesalzer3220]

Kern. Sweet.

[@StefanGotteswinter]

Thats what we have at work, yes. But they are by far not the only high-end cnc machines capable of cutting carbide.

[@aubreyaub]

Diamond is used the cut diamond.

[@cannonroberts5129]

Nice, thank you.

[@andrewwilson8317]

You got access to an XRF gun? Would be interesting to see just how pure the tungsten carbide really is? There is bonding agents to help with the sintering process. Last cutter I had checked had quite a lot of nickel in the matrix and I assumed that was to help with the sintering process? What's the difference between cheap and expensive tungsten carbide? Has to be the fillers and bonding agents?

[@Rustinox]

It's a bit like grinding HSS tools, but 10 steps higher.