think the pinion is something daft like a 0.05" imperial and metric equivalent aren't that great
I was talking about firberglass pen if com is dirty
when you replace brushes you may be able to jam the pen, wind the tip right out
jam it in there and let the pen clean up the com as you turn it
sandpaper is not advised as any harder and bits of copper may come off and cause shorts
which will involve stripping down.....
I was saying about brushing some carbon build up off all whilst motor is still intact and blowing out the carbon for an easy quick service
real frankentorque saddo's strip it all down recut the com's on com lathe or general lathe
pi$$ball about with different armatures and various cans & magnets...
redoing the shimming of motor and magnets rebuild shaft bearings if needed
(oh f*ck off, I have enough fun just shimming the f*cking gearbox)
yeah ffs - do a bit of servicing, box running well then get a new motor eventually
badly shimmed box will kill a motor's bearings quickly
but come on, even I draw the line at getting THAT involved rebuilding motors to attain max possible torque/speed balance
which tbh in UK @ 350fps we don't need really f*cking mental fast torquey bespoke franky motors imho