"Charles A. Sherwood" wrote in message
...

I primarly use HSS toolbits in my lathe and over the weekend I
ground a number of HSS lathe bits. I use a Baldor carbide
grinder with Norton 32A46 plate mounted grinding wheel.
I find that I have to dress the wheel very frequently when grinding
tough toolbits like MoMax.

Do you dress because the wheel has quit cutting, or because it has broken
down too much and is rough?

I tried grinding a 1/2 inch square
stellite toolbit and it was taking forever to reshape a used toolbit.

Where did you locate Stellite toolbits? The only ones I've found in years
were on ebay. If you're not familiar with them, you're in for a treat.
They perform at a level near that of carbide. Haynes Stellite is tougher
at red heat than at room temp.

I looked through J&L abrasive selection guide and they list
better grinding wheels for tool steels, but I cannot find any better
plate mounted grinding wheels. (I also looked at MSC). Any suggestions
on the best wheel to use for grinding HSS toolbits on a baldor carbide
grinder?

You are pretty much limited to an aluminum oxide wheel. For sure do not use
one made of silicon carbide.

I gather from your comments that you may not be using a hardness in keeping
with your requirements. The letter following your designation is all
important in that regard. If the wheel dulls up too quickly, the wheel is
too hard, so you should drop back a letter or two. If it seems to slough
off to quickly, go up a letter or two. (From J to L, for example).

As a side note, greee wheels are list as non-ferrous only and I had
a Norton 39C60 green wheel so I figured I would try it on the stellite
toolbit. It seemed slower than the 32A46. I was tempted to try my
diamond wheel but I was worried I would ruin it.

Do not use silicon carbide or diamond wheels on steel. Steel has an
affinity for carbon, and at the high speeds wheels run, the reaction is
relatively fast. The diamond or silicon carbide dissolves into the steel,
dulling the grain very quickly. In spite of the fact that silicon carbide
is a lot harder than aluminum oxide, the dulling from dissolution makes the
wheel appear to not be as hard. I don't know that Stellite would behave
in a similar fashion, but I've ground it with aluminum oxide wheels with
great results. I think the wheel grade you're using is the bulk of your
trouble.

A side note. I'm not all that nuts about using a 46 grit wheel for
sharpening toolbits, especially for finishing them. I'm inclined to run a
60 grit instead. It will cut slightly slower, and perhaps even a little
hotter, but the finish on the tool tends towards a much nicer one. Just
my personal choice, I don't mean to imply that should be good for everyone.

Harold