Hi Stefan,
You need a green wheel (silicon carbide) or diamond to grind tungsten
carbide. Diamond is great but rather expensive. Use a good quality wheel
as the cheap ones don't seem to cut as well. Wear a mask as you really
don't want to be breathing that dust. Don't use green grit or diamond on
steel as they will wear very quickly.
Carbide can take very high temperatures but it is sensitive to thermal
shock so let it cool in air. Quenching in water tends to cause fractures
in the material.
Les
Stefan Trethan wrote:
> I just tried to grind a simple cutter out of a broken carbide drill.
> The 1/8th inch shank is just the right diameter for M3 mounting holes.
> I've seen pictures of cutters on the web where half of the drill is simply
> ground away flat, so i tried that.
> I used a white grinding wheel in a plain (dry) bench grinder, and it was
> slow going, but the result works well enough to drill mounting holes.
> There is some burr at the exit, but compared to the commercial drills this
> tapered drill does not stall the small spindle i use for PCBs, which is a
> plus.
>
> That drill material is very tough stuff, and i don't have the right wheel,
> but it worked OK for a first try. Does carbide lose hardness if it gets
> too hot like hardened steel? I didn't bother to cool it much and it got
> orange hot quite quickly. It was only a trial so i do not mind if it is
> weak.
>
>
> ST
>