"Eric R Snow" wrote in message
news
On Tue, 22 Mar 2005 12:03:58 -0800, "Harold and Susan Vordos"
wrote:
"Grant Erwin" wrote in message
...
R. O'Brian wrote:
You luck is running good, MSC has them on clearance at about 40% off.
100 grit YQ04242426, 220 Grit YQ04242475, $54.75 ea.
You cannot purchase them on the net. Call 1-800-645-7270
Randy
Oops, my luck just ran out. MSC has no stock and isn't getting any
more, sigh. They're looking for me, they'll let me know tomorrow, but
as for now, I'm still looking for CBN plate mounted wheels.
Harold, please take it easy on me. I heard loud and clear that diamond
isn't the abrasive of choice for HSS, but lots of guys have told me
that borazon or CBN work really well for a finish grind. A Baldor No.
500 is a "carbide grinder" with tilting tables and plate-mounted
wheels,
and it runs at 3450 rpm. which is *way* too fast to grind HSS with
diamond, yes.
Grant
Shrug!
Ok, easy it is. However, I can't see a reason to use anything beyond
aluminum oxide. I especially can't see a good reason to use a carbide
type
grinder for HSS. At best, they're too restrictive to be functional.
One of the negatives of using a machine with a table is you'll *never*
gain
any skill at sharpening. As long as you permit a machine to do the
work,
you'll not progress. You'll also be limited as to how you can apply
your
tool steel to the wheel. I refuse to use anything that gets in the way,
including a work rest of any description.
I was brought up through the trade when there was almost no insert
carbide
tooling, and HSS was the order of the day, chiefly because brazed carbide
was still relatively new and not nearly as good as carbide is today. I
was
on the tail end of Stellite, which damned few that are machining today
can
claim. As a result, we were forced to learn to grind tools, or you had
to
find different employment. One was taught the basics, then was expected
to
apply them to sharpening. I can't think of any better advice for the
home
shop type. Any of the dodges you use to avoid learning will simply hold
you captive. That includes the grinder of which you speak.
Harold
Whoa Harold! With that logic we should throw away our milling machines
and break out the files. Forget files, we need to use stones. And have
to walk six miles back and forth through the snow.
Chuckle!
You must have had it good! I had to walk ten miles each way, and the snow
was deep---almost up to my hips.
Harold, I learned
how to grind tools by hand and with a grinder and rest.
So did I. Then I learned how to do it better from guys with proper
experience. I didn't close the door on learning.
The grinder
will put very nice edges on the tools and give you an example of what
a good grind looks like and and how a sharp tool cuts.
I do that free hand. *Anyone* can do it, all it takes is a little
practice.
The CBN wheels
used on HSS can give the tool a very smooth and sharp edge. Depends on
the grit of course. And wheel wear is negligible.
I don't see that as a positive thing. If you're doing repetitive grinds
on a production basis (cutter grinder), maybe it has its place, but I can do
free hand that which you mentioned, and I don't have to invest a large
amount in a wheel that is restrictive. I have no doubt these wheels are
good-----damned good----but they do not lend themselves as well to offhand
grinding as do aluminum oxide wheels. There are times when you simply
must dress a particular configuration into a wheel. CBN for that, too?
Why limit yourself to an expensive wheel that can't perform all functions?
There are no advantages, and it's far more expensive.
The point I'm trying to make is that all the fancy gadgets in the world
won't substitute for learning the basics. Learn the basics-----the rest
comes easy.
The best lathe men I ever worked with, one of which was likely the finest
man on a lathe of our time, (from South America, and spoke English poorly)
all sharpened tools free hand, for the same reason I do and did. Any rest
simply gets in the way. That's not to say you can't learn to grind tools
with them, but you'll never achieve the level of excellence that others do
without them. Grinding proper chip breakers is a good example of one of
the limitations when a rest is employed.
Harold