I’m rebuilding 45 year old electric motors, part of the rebuild of the mower deck of an antique electric tractor. This is an example of the level of corrosion we are talking about - unsurprisingly, this bearing does not move at all.
That’s all rust, no dirt. The metal shield’s eaten through in places.
I’m doing OK with fabricating disassembly jigs and through-bolts, I’ve got sources for upgraded bearings and brushes, the commutators clean up OK and the stator permanent magnets are intact and solidly bonded to the casings. But these motors have a reputation for developing sneaky shorts in the armatures, that my meters aren’t sensitive enough to pick up with caveman testing, and nobody I know has an armature growler, and growlers are too expensive for me to buy for the little amount of use I’d get out of one.
###Has anyone here built a DIY growler? @nixiebunny or @RossinDetroit or @shaddack maybe? Some Guy On the Internet™ has text here and there are pictures here and there’s a 1938 Popular Mechanics how-to here but that’s about all I’ve found.