How to turn carbide?

Ahm no 'spert, but... I think you gotta *grind* carbide. Fwiu, that's how cutters/drills are made to begin with. "Green wheels" are what we use to make lathe tools out of carbide blanks. They wear very fast, but remove carbide relatively rapidly.

Folks use green wheels, but smart ones use diamond wheels. :-)

The problem with the "green wheels" is that they're not all that much harder than the carbide, so it's tough on the wheels, the dust from which (silicon carbide) is very bad for your health, to say nothing of the carbide dust. The wheels tend to chip the carbide instead of cut it, so the end product (your lathe tool) leaves a great deal to be desired.

For the OP------turning carbide isn't something that you'd do with success. It's far too brittle and would chip instead of cut, leaving the trailing edge a mess, assuming you could come up with a medium that would machine it at all. It really should be ground with diamond or CBN wheels.

Harold

Dust indeed! So surprising how "apparently soft" green wheels are compared to grey Al oxide "rock wheels", yet, the grey wheels just get the carbide hot, while the green wheel really takes the carbide--and itself!--down.

Surprising also what is making the "hazardous" list. M42 (cobalt steel), is on there, wrt to grinding. Ditto chromium, etc.

Yeah, diamond wheels.... Open yer wallet.... :)

You can have diamond tools custom made, for actually less than you might think. We do a repeat specialized facing jobby using custom-made diamond cup wheels on a surface grinder, from a company in NJ--nice to deal with. Iffin anyone needs this type of stuff, email me and I'll dig up the partics.

Now the question is, how does one make *diamond tools*?? Abrasive jets & crazy glue, I guess. :)

You're confusing bond with abrasive hardness. Not the same thing. Silicon carbide (the green wheels) is much harder than aluminum oxide, but it is softly bonded so it breaks down rapidly to keep exposing new, sharp grain. Because it's intended for grinding tungsten carbide, they know the grain dulls quickly. They color code the wheels so you don't use them for other purposes, knowing they break down rapidly and wouldn't perform well. The typical silicon carbide wheel intended for other use is generally a shiny black color.

Aluminum oxide wheels are bonded much harder, but the grain is too soft to effectively grind tungsten carbide. The wheel glazes over and quits cutting, but because it's bonded much harder, doesn't break down very fast to expose new grains.

Harold

Nothing like a little clarification! Woulda never thought of that! :)