Inspired by thing:1483 I made an add-on to turn your dremeltool into a centrifuge. It has moving parts, but does not need support during printing or assembly afterwards. The trick to do this is use ball-and-socket joints, with a 0.2 mm gap between ball and socket. The shaft of a 3mm diameter nail was glued into the center hole of the add-on to interface with the dremel. I spun it at 35000 rpm, and it held out fine, but be safe and use this in a bucket!