I'll stick to my Dremel, I had two B&D tools, and bother broke down (no magic smoke lost), first one got replacedunder warranty, the second I pulled to bits and found that the drive from the motor to the work spindle was coupled via a short coil spring about 6 mm dia x 12 mm long, and the loop end of the spring had broken. A quick look in a box of springs, and about 5 minutes later, all back together and working. About 18 months later the magic smoke departed as the comutater collapsed in the motor.
Ian S C