Hi Bill...if you're talking "gravity"; I'm embarrassed to say I didn't think of that. I was just focused on creating a video.
Hi WBC... .01 inch/.254 mm is about 1/128 inch. WOW! Parts are definitely missing. I will pull the motors apart to see what's missing.
I'm pretty sure thrust washers at the top are missing. I would think I should be able to see them above the commutator.