Magnetic chuck resurfacing

[StephenK]

The magnetic chuck on my surface has reached a point where it should be ground. I have done it once which turned out to be quite a process. Would appreciate information on the proper way of doing this. Type of wheel to use, grit size, and a general procedure. I'll heed your advice. TIA
StephenK

[aboard_epsilon]

Assuming your talking surface grinders.
it's no big deal.
just make sure you are using a white wheel.
and not a green one .
there will be others that come along and answer this with answers like .
always leave the chuck turned on.
or dont leave the chuck turned on
always use suds when doing it.
or dont use suds.
or grind it as smooth as possiuble whilst others say grind with a rough finish.

All I can tell you is I didnt have the magnet turned on and I didnt use suds ..and my chuck is spot on .
all the best..mark

[toolmakerjim]

well theres your answer...jim

[Jpfalt]

If your mag table bolts down to a subtable it is also a good idea to pull the mag table off and give the subtable and base of the mag chuck a good cleaning.

At one place I worked we had a large surface grinder that was used for large castings and fabrications. The mag force could actually suck up the center of the chuck from the subtable and we often found grinding swarf between the mag chuck and subtable when we cleaned before resurfacing. If left, the swarf would allow more swarf under the center and the mag chuck would hump up in the center a few thousandths given enough time.

[wierdscience]

Like said above,white AOX wheel,80grit is fine,clean under the chuck,doesn't hurt to clean off the surface with the wheel either.

Technique I use is as follows,#1 dress and true the wheel.

#2 Make a pass over the whole surface of the table with the wheel just kissing the high spots.
#3 Pick one edge of the chuck as a starting point and advance the wheel down .001",make a pass over the whole table to the opposite side.
#4 Advance the wheel down .0005" make a pass over the whole table in the opposite direction and check your finish.

If it is 80% or better evenly cleaned up over the whole face,then thats good enough.If not repeat steps 1-4.No sense in grinding off more chuck face than needed.

If you remove the chuck for cleaning and or truing of the machine table,be sure that when you reinstall it that you indicate the edge of the chuck true with the table travel,this makes setups go much easier.

One more thing to keep in mind,this machine is for grinding operations,therefore the loads are extremely low as compared to milling.The tables of surface grinders are most times not very rigid.When you clamp a chuck or part to the table with hold downs,all that is needed are a few foot pounds on the bolts,tightening them too much will distort the table and cause problems.

[This message has been edited by wierdscience (edited 01-19-2005).]

[Mcostello]

Went on a service call to install a belt on a rotary surface grinder, while there a gent told me about the troubles with a B+S they had, would not hold any kind of tolerance. Had for many years with no trouble. After much troubleshooting they decided to remove chuck and replace with another. Hold down bolts rusted through and broke, was using coolant. Can you say LUCKY.