Eric - I've a similar sound that started recently - tinny vibration as
though the sheet metal in the start switching mechanism is loose? If you
find an answer, do post it.

Hul

wrote:
Tim said I should post this here also:
I have an old split phase induction motor that runs quite well.
Especially considering the fact that it is at least 60 years old. But
it makes a funny sound when running but the sound disappears
immediately whe power is removed. It sounds like something is a little
loose. Sorta like if the shaft was oscillating back and forth between
the thrust bearings. But it is not that. My son suggested that maybe
one of the windings is loose and rattles a little back and forth when
the polarity of the AC voltage changes. Anybody got a clue?
Thanks,
Eric