Job Numbers 180023, and 180061

Every now and then, not often, I get a watch like this. Plenty of power through the whole train, near perfect beat, excellent amplitude, no knocks of any sort, no hairspring issues, hand clarence fine, dial clearance fine, completely free balance, good mainspring, no barrel issues, etc, you name it...

It runs for a couple days then stops at random, right in the middle of the escapement cycle! It isn't even at an interval that would make sense if it was a particular pinion leaf or tooth. And when I look in there it immediately because perfectly fine again at the slightest touch.

This one is approaching a record for still being here. But now it's time to start replacing good parts by educated guess. I'm starting with the roller jewel.

Also, here's a new a new 16 size Waltham in for service; job number 180061.