Well, you told me, congratulations. That being said, the question is, is
the ruby color significant? Since all of the wheels I mentioned are
aluminum oxide, why is the ruby wheel better (in my experience) than the
others? The question was mostly directed at Harold, who is an acknowledged
expert on grinding.

Mark



"hg" wrote in message
.. .
I don't know how to tell you this, but a Ruby is AL203 == Aluinum Oxide in
a
trigonal chrystal structure with a hardness of 9. Diamond being a
hardness
of 10.


"Mark Winlund" wrote in message
...

"Harold & Susan Vordos" wrote


The red wheels, if they are the ruby red, are aluminum oxide, just as
the
old salmon colored wheels are.


Harold, I have wondered about that.... I have some fairly large ruby
wheels
I obtained years ago, and without exception, they are excellent on
hardened
steels... (by excellent, I mean cool cutting).... much better than the
white, and infinitely better than the grey aluminum oxide. I recently
found
some for my surface grinder, and they also work very well on cast iron
and
mild steel. Why are they red? Marketing hype? Why do they seem to work
better? I have other wheels just as coarse and soft acting, and they
don't
do any where near as well.

Mark