From ebay, i bought a OS Walker magnetic chuck for my surface grinder, and i thought i got a good deal, however it lacks the proper holding power.

Is there anything I can do to make it regain its strength?

Also, what is the proper procedure for installing a new chuck on a surface grinder?

how I've done it is clean everything, make sure the mating surfaces are getting full contact. indicate the fence (if it has one) or side to perfection using a tenths indicator. bolt it down but don't over tighten. indicate fence again. then spark out on a light cut to the top of the chuck.

who did you buy it from? if you bought it used, some idjit may have taken it apart; that's one way to demagnetize it. maybe OS Walker has a rebuild service, have you tried them?

How to i hold the indicator and to what should i square the fence to?