Archer
··Omega Qualified WatchmakerHoly smokes, good eye! Thanks for that, I feel better knowing what the issue is. I'll send it off.
How does something like this happen, just bad luck?
Based on your last note where you said it was running then stopping when you turned it over, I had an idea it was a floating screw. Good eyes aren't really needed if you know what you are looking for.
How does it happen? Well the simple answer is someone didn't properly tighten the screw down. To say why that happened would be more difficult. There are torque values given for tightening the various screws around the movement, and there are screwdrivers that can be set to the proper torque value, but none of that does any good if the screw wasn't gone back over to be tightened after the initial installation.
So bottom line is, people are human, and it was missed.
Cheers, Al