I assume you're saying that if the item contained ferrous parts the 60
Hz vibration shook everything loose? That's the only explanation I can
think of.

Jeff
Absolutely! The manager of the repair department got the idea because
when we shipped cameras back and forth on jets we always had to go
completely over them because a lot of the screws would loosen, high
frequency vibration.
I have seen lenses that I thought were completely frozen in total
pieces the next morning. Including some that had come apart in parts I
didn't realize they came apart in. Esp Leicas.
Richard