[Gareth1976]

At my old place of work, they did a lot of diamond turning, however, the carbide they were machining was 20-25% cobalt. The carbide we use here is 10% cobalt, so a lot harder and more brittle. Im putting the question out there that is it possible to diamond turn such a hard material? And if so, any advice on tooling, speeds and feeds etc will be very helpful. We have multiple CNC lathes, so we are equipped in that department. Our general sizes are between 3mm to 25mm, with our longest rod at 330mm.

Any help on this matter will be extremely helpful, thank you, Gareth.

[RCaffin]

At my old place of work, they did a lot of diamond turning, however, the carbide they were machining was 20-25% cobalt. The carbide we use here is 10% cobalt, so a lot harder and more brittle. Im putting the question out there that is it possible to diamond turn such a hard material?

Hard, very hard. I have used K20 to machine HSS, but the better sorts of HSS are a right pain to get the carbide into - especially with a light lathe like mine. The forces involved are very high, and the swarf or dust will play hell with ways etc if allowed to spread.

Possible, but is it really worth it?

The alternative is to use diamond wheels of various sorts to effectively do a toolpost grinder exercise. Yes, this creates some seriously abrasive dust too, but the forces are peanuts in comparison. Flood coolant or a large sheet of plastic over everything goes a long way.

By way of example, I made my own 2-axis goniometer and have been (dry) sharpening both HSS and carbide tooling (including end mills) with a simple RF30 mill. The rate of removal with diamond or CBN, and the lack of sparks, is pretty amazing. Using Alox is noisy and hot in comparison.

My 2c.