later In the preface I would like to say that I have been using Dremel for over 40 years, 8 of them a day so I can say I am quite familiar with Dremel and the use of sanding drums. 100% failure of the 1/2" rubber mandrel. If they lasted 5 minutes each, that's an incredible time. The rubber comes loose from the mandrel shaft and even though the drill spins the rubber with the sanding roller, no. ALL 10 WERE TOTAL failed.