Surface Grinder Basics – How to Dress a Magnetic Chuck – Tormach


Hi, I’m Mike Corliss with Tormach.
Today I’m going to talk about… ..mounting a magnetic chuck onto the surface
grinder, and then how to dress the chuck. You are going to be grinding the surface
of the chuck so you’ll want to pull the… …fence off because that’s just
going to be in the way. And then you’ll want to clean off the back. Spray lubricating oil on a sharpening stone. There now it’s nice and clean flat and then you’ll
want to do the same to the… …machine table. Give them both just a little shot of oil.
If you get coolant under… your magnetic chuck it
will start to rust, and then your magnet will grow and… …you’ll have a hard time getting parts
stay flat, so just give it a coat of oil. And then center it… with the ground pad on the grinder. Now I’m going to need an indicator. because I have to indicate the chuck in. Adjust the chuck until the indicator no longer moves. So now we’ve got the chuck square… with the travel of the machine. Now we have to dress our wheel and then
we can dust the top of the magnet so it’s square… …and level with the machine. When you dress in the wheel to grind the
chuck use a pretty rapid cross feed. …it need a more open grind. and the wheel will grind up cooler and
it won’t load up as much. You aren’t looking for a super good finish… …your more worried that a soft chuck.. …material will load up the wheel
and if that happens then it heats up and it warps your chuck. Ok, so now we got the magnet clamped on,
I adjusted the travel limits… …so we can dress the whole chuck, now you come down so we
just touch the magnet. I wanted go through by hand first.. Make sure we clear, Ok. That looks good. Then for the mode when I’m touching off I
have it in the straight line mode so… …it’s only gonna move the table in X. Turn my speed down, start the table, and then bring my speed up. The n once I have the table going back and forth and I can
bring the wheel down until… …it just about touches. I’m going to stop it.
Jog the wheel off. if you don’t have a coolant system set
up on your surface grinder, if you… don’t have a mister set up on it, I use vegetable shortening to keep the wheel
from loading up. And all you know you gotta do is
just put a thin film on it. We’ll use the step over motor You want it to step over while the wheel
is off the magnet. In this first pass, seeing how I really
don’t know how flat the magnet is… …I’ll just keep my hand up on the Z,
if it starts to… …hit pretty hard I can just raise the wheel. Now you can see how it just cleaned
up on the outside here hmm You just got to keep stepping it down until it’s… all cleaned up you don’t want to
take very much because… the problem with dressing it is the magnets are really soft and if you try to take too much your wheel will load up and heat up the magnet. and then your magnet gets distorted and then you’d have a hard time grinding workpieces flat.
The other thing is make sure… …you’ve got your magnet turned on
before you grind it. Usually I’d drop it about half a tenth
when I’m dressing a magnet, and then I’ll take a couple phantom
passes after I have it all cleaned up I’ll let it cycle back and forth three or four times… take the spring and make sure there’s no
heat in it. If you’re real careful you don’t have to
dress your magnet so much. If you’ve got a lot of sharp edges are you
are scratching your magnet quite a bit… this the stoning then your magnet’s
not going to be flat anymore… ..you’ll have to redress it more often.
There’s no real set time, you just go until… you notice your workpieces aren’t flat.
Just throw an indicator on it… and it looks like you’ve got a washout or what. That’s how you know if you’ve got to redress it. Ba doo bee doo,
Ba Doo…

10 thoughts on “Surface Grinder Basics – How to Dress a Magnetic Chuck – Tormach

  • Why is this surface grinder so slow?  It moves in the Y way to slow, and it has a pause at the end of every X stroke.  This is would take forever to grind anything, people would be better off buying a cheaper used surface grinder, would be so much faster.  This thing needs some serious upgrades to make it worth while for anyone to use.

  • Very helpful vid – I cant catch the name of the white paste you add due to no coolent system set up – 'vegetable shortner ??' What is it ?

  • Did you check the flatness after ground?  By myself, when you grind the magnetic chuck and show the spark, this chuck flatness fail, why don't use coolant?

  • Using the Crisco didn't work at all for me, rather, it clogged up the wheel substantially, and then left burn marks in the mag chuck. I had to redress the wheel, removing about 0.010" to get rid of the black crisco/Alu-oxide residue, and continue dressing the mag chuck. Worked way better without the crisco.

  • What about an electromagnetic chuck? Do you keep it on while grinding or should it be kept off. I'm concerned about heat.

  • Some people say its slow, yep, BUT, it allows you to do something else while that layer is being ground, my harig is nice but its manual and I have to stand there or nothing happens. So for a new grinder in this price range its great. This is a good feature even if its not as fast as a $30,000 or more grinder.

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