Bill wrote:

IIRC, someone provided some info about how to bore out the centers of
the wheels. I don't have a DP yet though, so I'm not sure where that
leaves me for the time being.

My recollection of drilling out the centers of the grinding wheels, is
that I didn't use a drill press. I believe I used a brace[1] as I wanted
to be sure nothing would get out of control on me. Once the bit
started chewing on the plastic, there wasn't much material in the
actual grinding wheel that needed to be removed.

[1]: The brace I used is a little different than the typical one you
find. Mine has four fingers in the chuck and can properly grip
standard drill bits.