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Subject: Re: [Homebrew_PCBs] grinding drills

From: "Stefan Trethan" <stefan_trethan@...>
Date: 2007-01-30

On Tue, 30 Jan 2007 18:55:30 +0100, Leslie Newell <lesnewell@...>
wrote:

> 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.

Ok, i think i even have green wheels somehere. I hope the colors are the
same here (is it inherent to the material or a code)?

> 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.

Uh, oh, .. good to know.. first one was only a trial, as i said... ;-)

I remembered that the tips are brazed onto drills and blades, so carbide
must be able to take some heat. But probably i should take it more slowly
so that it does not glow quite as bright....


Thanks

ST