"Ignoramus21124" wrote in message
...
OK, last dumb question, I swear.

Carbide inserts do not need grinding.

Brazed carbide bits cannot be ground with diamond.

Anything else can be ground with green wheels.

Why,. then, the need for diamond wheels?

i

Who told you brazed carbide can't be sharpened with diamond?
Better yet, who suggested to you that green wheels are an acceptable
compromise for a diamond wheel? I'd recommend you stay far away from that
individual, for he surely doesn't know what the hell he's talking about.
Mean time, NEVER use a silicon carbide wheel for grinding steel. That is
just as stupid as using diamond for steel.

You are very best served to take advice from those of us that have actually
worked with these grinders. I have, and have extensive experience in hand
grinding lathe cutting tools. My advice will serve you perfectly well and
keep you out of trouble. I can, and do, grind toolbits that work, and work
as they are supposed to work. I am not lost on the subject of grinding
toolbits, and have many years to my credit, and have authored several
documents that are available for those that care to learn the art of
grinding toolbits.

Sharpening brazed carbide toolbits is very best accomplished with a diamond
wheel. In order to achieve the desired results, you must relieve the
supporting steel substrate. That's not a big issue, and is easily
accomplished by simply grinding a slightly greater relief angle that that
which is ground on the carbide. Using the existing carbide as a guide,
grind the steel beneath the cutting edge until the wheel is grinding on the
carbide. You'd use an aluminum oxide wheel for this task, which is too soft
to move much carbide, so it is more or less self gauging. You now have
prepared the tool to be ground on a diamond wheel, which should be run wet,
and supported by a table that can be set for the desired amount of relief.
If, in the process of sharpening the carbide, you must remove enough to make
contact with the supporting steel once again, regrind the steel with the
aluminum oxide wheel. None of this is difficult.

A good idea is to have a wet diamond on one end of a double shaft motor,
with an aluminum oxide wheel on the opposite end. That way you are properly
setup to sharpen both brazed carbide and HSS with one grinder. I have
operated in that manner since 1967 with excellent results.

Harold