I've got a H/F lathe tool grinder, a copy of a Balder or something. Any
way I have read that the green wheels are for carbide but that you shouldn't
sharpen tool steel on a green wheel. I'm thinking about getting a diamond
wheel to put on this and was wondering if tool steel can be sharpened on the
diamond wheel? Also, which diamond wheel would you get if you could only get
one, coarse, medium or fine? As always, thanks in advance for your comments.
This is by far my favorite forum.
Dick

--
Richard H. Neighbors
Building and repairing fine billiard cues for real pool players at
affordable prices.
Over 35 years exp. Located in Cincinnati OH
ph.# 513 233-7499
e-mail
web site http://www.dickiecues.com

Lots of old wive's [or old machinist's] tales about this. Some
of these are even true in a production environment, which won't
apply to low volume, lack of time pressure hobby or home shop
machining.

General rule is that you don't want any combination of tool and
material which will "react." For example, iron is known to
dissolve carbon when it is hot/molten. Thus you want to avoid
green [silicone carbide] or diamond wheels on steel. This holds
true for cutting tools as well. Diamond tools don't work too
well/long machining steel. Ceramic [aluminium oxide] tools don't
seem to last too well on aluminum.

Having said that, with the light use a typical grinder gets in
the home machine shop you most likely won't see much difference.

Biggest single tip is to keep your wheels "dressed" so they will
cut rather than rub. If you use aluminium oxide [white] wheels
the silicone carbide blocks, typically 1" X 1" X 6" will do a
fine job. If you use the green rocks, I suggest buying a
inexpensive diamond dresser [ 10$] and fabricating a holder out
of a square or rectangular piece of steel. Normally the diamond
dressers are round and tend to get away from you. Remember to
rotate the diamond in the holder block to avoid grinding flats on
it and it will last you a lifetime.

Take a look at my website in the craft machining section to see
the tool grinding fixtures we made as a class project.
see: http://www.mcduffee-associates.us/machining/thfnce.htm
and http://www.mcduffee-associates.us/ma...g/tabanggg.htm
With these and a machinists protractor, even the first term
students were able to grind a "line-out" acme thread tool. It
won't make that much difference if the HSS gets hot (see how hot
it gets when you are cutting), but try to keep any carbide tools
cool and never dunk hot carbide in water as this will cause
microcracking and it will quickly fail in use although it may
look fine.

One trick is to use a 5 or 6 inch diameter abrasive loaded nylon
brush in a drill press at medium speed. These are commonly
available in hardware stores and have blue bristles with a 1/4
inch shank. Use on the your new ground tool to give the effect
of hand honing in removing the wire edge. Also works well on
resharpened drill bits.

If you have not done so I suggest you buy the South Bend and
Sheldon lathe book reprints from Lindsay. These give a good
explication of the terms and have lots of pictures.
see http://www.lindsaybks.com/bks/lathebk/index.html

Just don't get discourages when the right hand tool your were
grinding turns out to be left handed. It has happened to
everyone.

Uncle George



On Fri, 02 Dec 2005 01:14:17 GMT, "Dick"
wrote:

I've got a H/F lathe tool grinder, a copy of a Balder or something. Any
way I have read that the green wheels are for carbide but that you shouldn't
sharpen tool steel on a green wheel. I'm thinking about getting a diamond
wheel to put on this and was wondering if tool steel can be sharpened on the
diamond wheel? Also, which diamond wheel would you get if you could only get
one, coarse, medium or fine? As always, thanks in advance for your comments.
This is by far my favorite forum.
Dick

"Dick" wrote in message
...
I've got a H/F lathe tool grinder, a copy of a Balder or something. Any
way I have read that the green wheels are for carbide but that you
shouldn't
sharpen tool steel on a green wheel. I'm thinking about getting a diamond
wheel to put on this and was wondering if tool steel can be sharpened on
the
diamond wheel? Also, which diamond wheel would you get if you could only
get
one, coarse, medium or fine? As always, thanks in advance for your
comments.
This is by far my favorite forum.
Dick

Diamond wheels should never be used for grinding steel or iron unless the
surface speed is reduced such that you can't generate any red heat.
Diamonds are quite rapidly dissolved by the metal otherwise. The result is
dull diamonds, which create more heat, which dissolve all the faster.
There are no exceptions to that rule, regardless of application. Home shop
makes no difference, for the diamond has no idea of knowing that is should
be forgiving.

Green wheels are silicon carbide, and, like diamond wheels, are readily
absorbed by steel at high temperatures. The net result is a rapid dulling
of the wheel, necessitating frequent dressing. Because the wheel is
absorbed by steel, it is dulled almost instantly and glazes over, refusing
to cut. Silicon carbide wheels (not green ones) should be used for all
non-ferrous applications, and for cast iron. Aluminum oxide wheels
should be used for steel.

Green silicon wheels are bonded such that they break down rapidly to keep
exposing fresh grain, an offset for grinding carbide. It is much harder
than even heat treated steel, so the grains dull quickly. When you grind
softer materials, the result is rapid shedding of the grain, so wheel life
is seriously reduced. While that is an inconvenience, the real threat is
in breathing the dust. Silicon carbide can be the source of silicosis.

Dressing grinding wheels for off-hand grinding should not be accomplished
with a diamond. Such a dressed wheel will always cut excessively hot, and
require considerably more pressure to achieve an equal amount of work as
compared to a wheel that is dressed by either a star type dresser (I don't
like them), or a dressing stick. Using a diamond to true the wheel is a
great idea, but the surface should then be slightly roughed to break the
fine surface created by the diamond. The difference is readily noticeable
when you use such wheels. Star dressers provide the best of all surfaces
for off-hand grinding, but they can be difficult to use, especially when the
stars have considerable wear on the pivots, and they often are quite
wasteful of your wheels. Dressing sticks provide a surface almost as
good, and are much easier to apply. Make certain your choice is not a
solid boron carbide type dressing stick. The one that serves your needs
best is a sintered silicon carbide stick, relatively coarse. They are
available in 1" square sticks, usually 6" long.

Harold

On Fri, 02 Dec 2005 01:14:17 GMT, "Dick" wrote:

I've got a H/F lathe tool grinder, a copy of a Balder or something. Any
way I have read that the green wheels are for carbide but that you shouldn't
sharpen tool steel on a green wheel. I'm thinking about getting a diamond
wheel to put on this and was wondering if tool steel can be sharpened on the
diamond wheel? Also, which diamond wheel would you get if you could only get
one, coarse, medium or fine? As always, thanks in advance for your comments.
This is by far my favorite forum.
Dick

I have the same Baldor clone, and the same wheels. I have no idea
what those wheels are, but they're far harder than any other "Green
wheel" I've ever used. Even with a diamond dressing, they don't open
up and cut, not even HSS. Grinding the steel on a brazed carbide tool
with a good wheel would normally leave grooves in the green wheel,
with these, the metal only takes a nice polish, which isn't what I was
after.

They do nicely for my wood lathe chisels, but seem to generate more
heat than work.

Diamond wheels cutting HSS will plug very rapidly, most often burning
the cutting edge rather than sharpening. For just "touching" the
cutting edge, to get a really sharp tool, they work ok, but any more
than just a polish and they plug.

My choice, were I to buy only one diamond wheel, medium. The fine
wheels can give a beautiful edge, but can also take forever if you
have to take any amount off. The coarse wheel leaves scratches behind
that are enough to start a crack.

Rich.

Note that the Drill Doctor successfully uses a diamond wheel to sharpen
HSS, as do chain saw sharpeners.

Personally I use an aluminum oxide wheel for coarse grinding to shape
and a silicon carbide one for final finishing and have had no problem.
Last night I resharpened an HSS lathe cutoff bit on the SiC wheel to an
edge that peeled smooth, shiny steel foil off a Grade 5 bolt without a
hint of chatter.

jw

Another "trick" is to put a fine green wheen on one side and a
fine white wheel on the other side. Use a belt sander with the
zarconium oxide belt [blue abrasive] to rough out your HSS tools
and the fine rocks to polish. Most likely you will only be
touching up any carbide so the fine wheel will be adequate for
that.

Most any of the inexpensive 4X36 belt sanders are adequate. Even
better if it comes with a disk. Get 600 or 1200 grit disks from
the automotive paint section and polish your tools to a high
gloss.

Uncle George

Dick wrote:

I've got a H/F lathe tool grinder, a copy of a Balder or something. Any
way I have read that the green wheels are for carbide but that you shouldn't
sharpen tool steel on a green wheel. I'm thinking about getting a diamond
wheel to put on this and was wondering if tool steel can be sharpened on the
diamond wheel? Also, which diamond wheel would you get if you could only get
one, coarse, medium or fine? As always, thanks in advance for your comments.
This is by far my favorite forum.
Dick

Most diamond wheels should NOT be used on regular (high speed) grinders
to grind steels. They are fine for carbide. The same is true for the
'green' Si-Carbide wheels. Grinding steels will soon wreck either type
wheel. Note: ... there are LOW speed diamond wheel grinders that can be
used on steels (Glendo, etc.) ... these are a whole different animal
than the so called 'carbide' grinder you purchased.

For common tool steels you should get a 'white' aluminum oxide wheel.
These are available with the steel backs as required for this type
grinder. MSC has them, as do others.

One thing to watch out for. I bought two of the HF grinders, one for my
home shop, one for university where I work. They are generally
satisfactory, BUT ...

One cast-iron wheel guard on one grinder was bored a bit off center. No
problem with the 'green' wheels provided. I ordered two 'white' wheels
from MSC, and these were about 1/8" larger in diameter. That was perhaps
1/16" too big to fit in the off-center wheel guard.

I solved the problem by unbolting the bad wheel guard and setting it up
on the rotary table on my mill, then milled out the inside of the guard
to approximate concentricity with the mounting hole. Only a small amount
needed to be removed from one side of the guard ... ample thickness
remained. I used a ball-end mill to avoid any sharp stress-riser
internal corners. Now it works fine. This was a minor job for anyone
with a mill. I suppose it could have been done freehand with a die
grinder and some care.

Considering that the HF grinder is about half the cost of the other such
imported grinders, it seems a good value, even WITH the added work on
one of four wheel guards. It's a just typical HF (and imported in
general) quality control problem.

Dan Mitchell
============

Thanks to all that replied. I guess I'll get a white wheel for tool
steel and a med. diamond for carbide. Thanks all for the information.
Dick

--
Richard H. Neighbors
Building and repairing fine billiard cues for real pool players at
affordable prices.
Over 35 years exp. Located in Cincinnati OH
ph.# 513 233-7499
e-mail
web site http://www.dickiecues.com
"Daniel A. Mitchell" wrote in message
...
Dick wrote:

I've got a H/F lathe tool grinder, a copy of a Balder or something.
Any way I have read that the green wheels are for carbide but that you
shouldn't sharpen tool steel on a green wheel. I'm thinking about getting
a diamond wheel to put on this and was wondering if tool steel can be
sharpened on the diamond wheel? Also, which diamond wheel would you get
if you could only get one, coarse, medium or fine? As always, thanks in
advance for your comments. This is by far my favorite forum.
Dick

Most diamond wheels should NOT be used on regular (high speed) grinders to
grind steels. They are fine for carbide. The same is true for the 'green'
Si-Carbide wheels. Grinding steels will soon wreck either type wheel.
Note: ... there are LOW speed diamond wheel grinders that can be used on
steels (Glendo, etc.) ... these are a whole different animal than the so
called 'carbide' grinder you purchased.

For common tool steels you should get a 'white' aluminum oxide wheel.
These are available with the steel backs as required for this type
grinder. MSC has them, as do others.

One thing to watch out for. I bought two of the HF grinders, one for my
home shop, one for university where I work. They are generally
satisfactory, BUT ...

One cast-iron wheel guard on one grinder was bored a bit off center. No
problem with the 'green' wheels provided. I ordered two 'white' wheels
from MSC, and these were about 1/8" larger in diameter. That was perhaps
1/16" too big to fit in the off-center wheel guard.

I solved the problem by unbolting the bad wheel guard and setting it up on
the rotary table on my mill, then milled out the inside of the guard to
approximate concentricity with the mounting hole. Only a small amount
needed to be removed from one side of the guard ... ample thickness
remained. I used a ball-end mill to avoid any sharp stress-riser internal
corners. Now it works fine. This was a minor job for anyone with a mill. I
suppose it could have been done freehand with a die grinder and some care.

Considering that the HF grinder is about half the cost of the other such
imported grinders, it seems a good value, even WITH the added work on one
of four wheel guards. It's a just typical HF (and imported in general)
quality control problem.

Dan Mitchell
============