On Fri, 06 Dec 2019 14:38:18 -0800, wrote:

I have been grinding and lapping carbide tools for about 40 years.
I have been given conflicting advice about slow grinding and lapping
carbide with diamond wheels.
Whether using a plated wheel or a cast iron wheel charged with
diamond I have found that the most common advice I have been given and
also seen on youtube recently is wrong.
But the advice I was first given turns out to be correct. For the
best edge when using a slow speed grinder, such as a Leonard
Grind-r-lap or an Accu Finish, the grinding should be such that the
wheel surface moves away from the edge. Not into the edge.
With the wheel moving away from the edge the part being ground will
tend to be lifted from the table. This is a bit of a hassle but the
edge will be better.
When rough grinding I have the wheel moving into the edge but
reverse the rotation when getting the final edge.
I have been told many times that my method is wrong, that it will
chip the edge. This has not been my experience. I get a better edge.
Sharper and with no chipping.
Not only do the tools cut better and last longer, which is the best
test, but under a microscope the edge looks better.
I just looked at some inserts I ground special for a grooving job
using a very nice UNITRON metallurgical microscope at 600 x
magnification.
Wheel rotation into the edge rounds the edge slightly, while
rotation away does not. And the carbide does not chip.
Incidently, when I first started using a slow speed grinder it was
a Leonard Grind-r-lap, and the instructions with the machine said to
grind away from the edge when using diamond abrasive on carbide. I
still use one of these machines. I bought it used years ago because it
does such a good job and is so easy to use.
I hope this helps somebody.
Eric

Thanks!

Gunner
__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

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