@Robin2: if you can turn yours by hand then it clearly isn't the same design. I gave a link to the specific device I had in mind, I never said that all cheap cordless drills work that way. I was equally sceptical when Zoomcat described the tool, but my opinion has been changed by actually getting my hands on one. I see you're in the UK, so if you're interested then perhaps you might invest the eight quid to check it out. It's a decent price even compared to buying a bare hobby motor.