Homebrew PCBs

Stefan,

Carbide can take a LOT of heat, but glowing red or white hot isn't 
such a good idea.  As mentioned, don't quench it if you don't have 
to but it shouldn't hurt in reality.  A green grinding wheel is very 
soft by comparison to the white one you are using now.  It will 
abrade away very quickly - the nature of the beast when grinding 
carbide.  Don't inhale any of the carbide dust - it's nasty stuff.

The type of tool you ground is referred to commonly as a half round 
drill.  They work great in many materials including brass, copper, 
plastics and even glass.

Recently I tried to grind one for isolation milling - what a joke 
that was.  I just don't have the eyes for it anymore.  I tried all 
my optical aids and nothing would bring the grind into focus to see 
what I was doing. 

The burr you are getting is probably caused by not having clearance 
on the backside of the cutting edge.  It is very hard to visualize 
where it (the clearance) needs to be but if you look at a normal 
drill, you will see how the backside of the cutting edge rises up.  
The half round drill needs this as well, but it is very minimal when 
done correctly.

With all that being said, you must have done pretty darn good if you 
ground the drill with a white wheel and got it to cut a hole in the 
end!!!

Chris