[_paralyzed_]

I think this guy needs some reassurance! You can do it. You can't hurt your pretty motor. Grind away! If you're afraid of removing too much (you can't unless you remove half or more) align your gears, figure out where the grub screw will hit, and only grind there. It only takes a little flat spot. if you're scared use a file, I wack mine with a cutoff wheel and a dremel, you're making it way more difficult than it is. Get flatspotted!