I bought some third-party filament and the spools it came on had a smaller hole in the hub than the Makerbot spools. I decided to enlarge them to fit my existing spindle using a 2" hole saw, and needed a way to keep it centered over the hub. The simplest solution seemed to be to print a bushing for the pilot drill, that fits in the existing hub.Hot glue it into the hub to keep it from riding up the drill bit. The bushing can usually be pried out and reused several times, if you're doing multiple spools.