I need to enlarge the potentiometer holes on a semi-hollow Epiphone for a new harness. The last time I did this on a Les Paul with a drill bit, even though I went slowly, there was chipping of the paint and wood around the hole. The damage was covered by the washer, but I would like to avoid this on this new guitar. Any tips? I've got a hand drill and a dremel with a bunch of different attachments.