There was a person on here that did his flywheel fins on a drill press. He mounted the fly wheel on the the drill press chuck with the largest bolt that would go through the hole and flat washers and nut tightened down. The bolt was then fastened into the chuck.

Square your table with the spindle and mount a a hard board with some coarse sand paper using spray contact cement. - sand away.

Then you still have to balance it and you can only sand as deep as the beginning of the counter weights.

You have to balance with the die grinder and balancer.