On Sat, 30 Aug 2003 02:10:54 GMT, (Kenneth W. Sterling)
wrote:

Gang,
I have sent some pictures to the dropbox to reference a problem I'm
having where I work.
The links to the pictures in the dropbox a
http://www.metalworking.com/dropbox/magchuck.txt
http://www.metalworking.com/dropbox/magchuck1.jpg
http://www.metalworking.com/dropbox/magchuck2.jpg
http://www.metalworking.com/dropbox/magchuck3.jpg
Thanks for any suggestions.

Couple of things come to mind, Ken. The first is that it appears the
squarish base of the cutter doesn't quite reach to the concentric pole
immediately outside the center pole, except at the very tips. You've
just thrown away a good deal of your holding power with an air gap. A
conventional rectangular magnetic chuck with closely spaced
alternating parallel poles would most likely straddle more of the
base. If you are stuck with the circular chuck, then quarter circle
pole pieces made out of soft iron to extend the annular ring magnetic
flux up into the body of the cutter and thence to the central pole
would be helpful - would also provide an anti- torque arm to resist
the grinding wheel torque. The only touchy thing would be in making
the base of each quarter section the same thickness as the annular
ring it abuts or you'll lose some of the flux to leakage to the other
two poles on each side.

Best wishes,
Mike