ATM : Hole in the middle

["robert allen" <rallen@iland.net>]

                We got a problem. The A.S.K.C. has ground and
        smoothed a 20" blank with a 3.5" hole in the "middle". The
        work was done with a "plug" held in with dental plaster and
        the grinding went well with a 16" tile tool. 
                BUT, at the first attempt to polish we found severe
        scratches and sleeks around the hole from debris picked up
        from the depressed ring around the "plug". The "plug" was
        removed and the smoothing was redone. 
                We are now ready to polish but cannot decide how 
        to build a lap that can be pressed properly. 
                Hope some one out there has beat this problem before.
        We are wide open for advise or sugestions. 

                                HELP !!!     Bob Allen