If anybody ever built one of the star trek/star wars fiber optic models you may still have the 2AA batt. drill they included in the kits.I know a lot of people who bought these kits and broke their bits within 30 min,if you were lucky enough not to at 3volts it would still melt plastic.I used one in which I ran a jumper wire where I could use 1batt.(1.5v) and it worked great,recently working on the inst.panel on the 1:12 mercury spacecraft I noticed the indented mold marks,while these are no problem to fill,sanding is a different story.I took the drill minus bit to Hobby Lobby and perfectly matched a dowell rod to the drill,I then cut about 3 inches off the rod,then drill a hole perfectly centered in rod slightly smaller than the motor shaft,push the rod into the drill assembly,I used no glue but it is probably a good idea.I then take testors sanding films using a punch and punch out discs of different grits the same diameter as the rod.Apply rubber cement to back of disc and tip of the dowell,wait 5 min. and stick disc to dowell,you now have a batt.powered micro-orbital sander for those hard to reach places! i.e.(circuit breaker panel) this works great !