Ok I have my delta surface grinder up and running all looks good. I did a
small test plate and it seems to do the job. I have never used a surface
grinder so any tips, how to, or DON'T does would be good. not sure how fast
to feed, how much ect.
Take light cuts. I can't emphasize that enough.
I watched my boss blow up a wheel and take out a wall when feeding
around .010" on tool steel gear cutter bits. Don't force it. If the
wheel starts slowing down you are hogging off too much, reduce down
feed or cross feed or both. Oh yeah, never start to wipe off the water
on the magnetic table until the wheel has -completly- stopped. I lost
a couple of knuckle tops that way.
Your machine probably has a manual table feed so going too fast won't
be too much of a problem. The hydraulic table feeds can really force
things and the wheels can't take much of that.
Best of luck with it. 73 Gary
Feed as fast as you want..but only take off a few tenths (.0001) at a
time. Depending on wheel, and material, sometimes you can go fat and
take off up to a thousand..but you will likely wear the wheel fast and
get burn marks on your material. Plus the finish may suck as the head
A heads up. The wheel needs to be dressed with a diamond dresser
(cheap) and aways...aways...aways start high. If you screw up and
start low..and hit the side of the workpiece..you could grenade the
wheel. Not a fun think even if it doesn't hurt you.
"That which does not kill you,
has made a huge tactical error"
I strongly disagree with grinding instructions you've received. If my
opinion matters, here's a link
that will take you to a site where grinding is currently being discussed.
My posts clearly state a procedure for grinding that is far superior, and
explains why. There is some very good information provided for anyone
that desires to learn to grind well.
This is a problem that can have so many causes that it's almost beyond
the scope of a post.
First, how are you grinding? Are you subscribing to the notion that
you should constantly down feed your wheel and take large swaths with
each pass? You'll never achieve what I consider a good finish by that
method. You must learn to grind in a different manor.
Are you grinding dry? Heat alone will give you more problems than
you'll ever be able to overcome. If so, no matter what it takes, get
your grinder running with coolant unless you're grinding small items
like punches. Grinding creates an enormous amount of heat, which must
be dealt with. The expansion of the work makes holding a tight
tolerance almost impossible, to say nothing of the poor finish you're
likely to get regardless of your effort.
Are you grinding soft materials? Cold rolled steel, for example? Soft
material never grinds as well as hard material, but you can get a good
surface void of waves when things are right.
To change how you grind, I suggest the following:
Think of your grinding wheel as a milling cutter, which it really is.
It is a multiple toothed cutter that will cut very best by using a
corner. Try grinding your objects by picking up, then moving over to
the edge and feeding down a reasonable amount. If you have .010" to
remove, and it will come off one side, take .005" and run across your
item repetitively, feeding the cross slide roughly .030"/.050" each
pass, allowing the corner of the wheel to take all the meat off. Take
all your passes in this manner, with no down feed until you're ready
for the next pass. By grinding in this manner, the wheel takes all the
meat off with the corner, leaving the balance of the unaffected wheel
to constantly spark the surface. That yields the best finish, and is
actually much faster than grinding by the plunge method. It creates a
shoulder on the wheel that must be dressed off when it becomes a
problem. You'll know when, because the wheel doesn't cut well. It can
be because it's gradually developed a tapered shoulder, or it's
loaded. Loading is usually caused by the wrong density of bond or
wrong hardness of wheel.
The very best scenario when grinding is that you grind both faces,
whether they require it or not. That way you keep stress in balance,
so the part tends to remain flat. Try to take equal amounts off both
faces, even when it's not necessary. Your reward will be flatter
parts. Don't take it off one side then the other, take a cut, flip the
part, take a cut, flip the part, etc., until you're to finished size.
That's the best way to achieve a good finish and a flat part. Your
final pass should be something like .0005", with a freshly dressed
If you have a manual grinder, you're not nearly as likely to be happy
with this process as you might be if you have a hydraulic feed
machine. Unless you're involved in fine toolroom grinding, I highly
recommend you avoid manual machines. I've done some very difficult
toolroom grinding with several hydraulic machines, but can't imagine
grinding large surfaces with a manual one. You can turn on the
hydraulic machine and grind as I recommend while you're doing other
Be certain that you have matched the wheel to the work at hand.
Aluminum oxide wheels for steel, always. Never silicon carbide. Using
a silicon carbide wheel on steel creates a glazed wheel almost
instantly, and that generally leaves a wavy surface. Too hard of a
wheel does the same thing, and a too soft wheel breaks down so fast it
almost always leaves a rough finish.
Wheels that are properly selected will cut without loading and leave a
decent finish, assuming your grinder has not had the motor replaced by
another motor (that has not been precision balanced), and has good
spindle bearings. Even a V belt can cause your finish to suffer. It
must run smoothly and not transmit any type of motion to the spindle.
The slightest vibration will translate into a poor finish. As little
as a few hundred thousandths variation show up as waves in your
finish. Use a hard wheel for soft material, and a soft wheel for hard
material. Wheels must break down at a proper rate (to stay sharp) in
order to achieve a good finish.
Are you running your grinder single phase? You're likely to never get
a good finish if you are. The uneven power pulses tend to translate
into the finish.
If you can provide more information I may be able to provide some
Excellent post Harold
"That which does not kill you,
has made a huge tactical error"
First this guy just bought a Delta toolmakers grinder.
Its is about as light weight as you can get, so advising the guy
to take 5 thou is very bad advice! Believe me, I own the rockwell
version of this machine and it won't do it! Period.
Second. This machine is not equiped with flood coolent. Mist
coolent was an option. I have never tried using coolent because
of health concerns but I'm sure it would work better. I have done
a lot of grinding dry with decent results. Definately a step
up from the milling machine.
I own a small lightweight (1500 pounds) 6x12" manual surface grinder. I'm not
real good at getting terrific finishes either. My grinder manual says to ease
the corners of the wheel with a dressing stone, and this helped quite a bit
for me. I've always gone with the .0005" downfeed, wide crossfeed, and I'm
going to try Harold's .005" downfeed, .020" crossfeed.
I hooked up flood coolant when I ground in my mag chuck. It somehow got under
my table and turned the way oil to jelly. I haven't tried coolant since. Most
of the things I grind are pretty little, though.
I'm also planning to try precision balancing my wheels. Eric Snow told me
recently that little grinders really work better with perfectly balanced wheels.
The comments (in the post that was copied from a different site) were
directed to a person that was operating a B&S machine, not for the owner of
a Delta. However, everything stated still applies-------perhaps with a
lighter depth of grind. Regardless of how rigidly a grinder is built,
surface finish will be profoundly improved by the method proposed. Coolant
is a must-------it's not a luxury.
I'm not sure I understand your concern for using coolant and your health.
Are you suggesting it's healthier to breath the metal particles than some
mist? You want to remain healthy? Quit working with metals. There's
a given risk for those that do---------it goes with the territory.
When you suggest you've achieved decent results, try selling your results to
a QC department. It's all a matter of what you deem acceptable. My time
on grinding machines tells me that there's no way in hell you'll come close
to the results of grinding wet----and that includes holding dimensions.
Typically, grinding is close tolerance work--work that is rendered nearly
impossible when grinding dry. If, on the other hand, you have no clue
about working to tight tolerances, perhaps that's not a concern. For me, it
was. I'm afraid I'll have to put my years of experience in precision
grinding up against your opinion.
Its pretty easy to wear a half face dust mask to avoid breathing
the dust and to clean up aftewards.
I don't know how to deal with mist coolent. Seems like anything
wet would plug up a resperator pretty quick and you have to
deal possible machine damage by the moisture as well.
No doubt that coolent gives a better finish, but for a small
rockwell/delta toolmakers grinder (like I have ) your not going
to compete with a real surface grinder anyway.
To me it easier to deal with the devil that I know vs the
devil that I don't know.
Use good judgment in the depth of grind. My comments were (originally)
directed towards a much more robust machine, a B&S.
When you use my proposed method, do *not* modify the edge of the wheel.
That's no different from a wheel that has already done considerable work.
It's the corner of the wheel that does the work by this method. You want it
as close to a right angle as possible. It's when it becomes tapered that it
becomes necessary to dress the wheel.
One other thing. Again, my (original) comments were directed towards a
machine that is built for coolant. I fully understand your reluctance to
use coolant if you've had a negative experience----like running coolant on a
cutter grinder that is intended to be run dry. I obviously wouldn't
recommend coolant on dry machines---but I also wouldn't own a dry machine
when coolant was a *requirement* for good success. I practice what I
When reading the posts I realize the grinder I have will not take a .005
cut, however alot of the information very usefull. I think .001 is about the
largest cut I would want to make with this grinder, making small advances at
this depth gave very nice results. Sure it takes time but I don't have the
need for a 3000 pound machine for how often I will use this. Now its time to
find some other wheels and experiment. I sparked in the chuck and it seems
very accurate, and smooth.
Thank ypu for the great information and I look foward to any other posts.
What Harold says. I sometimes will dry grind a small tool but it is
really slow compared to using mist or coolant. I just finished my
grinding room and it has two exhaust fans. But having even some mist
on the part will actually be better than the fines that come off of a
grinding operation. The water will get the fines to clump together
into larger size particles. I noticed this helps the amount of dust in
the air. Especially when grinding cast iron. Even with a mask you will
smell iron for hours after grinding cast iron dry.
"Harold and Susan Vordos" wrote in
I was beginning to think that I was the only person that grinds on a
surface grinder that way. I've got a question for you Harold. Have you ever
done any double disk grinding? I'm looking for a wheel supplier, and maybe
some advise. Very tight tolerance parts on a brand new very accurate
machine with auto sizing. I'd sure appreciate any help you can offer.
"Waynemak" wrote in
The power required is a function of the depth and cross feed. Reducing
either reduces the power required. Take .0025" and cross feed .010" and
you've reduced the power required by 1/2.