Flats on a bearing surface

[Sjk4x4]

Ive not encountered this before and wanted to ask if it is more common than I think it is?

This is a Molniya pocket watch from '59.  Its a beautiful and purposely thin movement. 

In the photo is the fourth wheel and needs the seconds arbor repivoted. The glare on the bearing surface that rides in the jewel is a flat and there is one that aligns with every valley in the pinion.

Its polished so i imagine its factory and may be done to reduce friction? Just guessing here. Anyone else have experience with this?

 

 

[HectorLooi]

The flat part does not appear to be contacting the jewel. The pivot appears very short. Is the pivot broken?

[jdm]

6 hours ago, Sjk4x4 said:

The glare on the bearing surface that rides in the jewel is a flat and there is one that aligns with every valley in the pinion. 

That is because to cut correctly the leaves of the pinion to the given depth the cutter removes also a bit of material in there. Then it's polished so the resulting edges don't interfere with the jewel.

 

2 hours ago, HectorLooi said:

The pivot appears very short. Is the pivot broken?

So it is, as the OP had mentioned. I never heard of a seconds hand pivot being refitted to a pinion, and I'm a bit skeptical about it's practical feasibility. 

[oldhippy]

I would say that pivot has at some time broken and has been cleaned up and polished.  

[nickelsilver]

As JDM said, those marks are a remnant from cutting the pinion leaves. As that surface is nonfunctional, it's just a cosmetic issue.

 

As for repivoting a 4th wheel, it's a common job. It's best to make a stepped plug, so that there is a bit of a shoulder at the pivot/pinion interface so that the pivot doesn't pull out when removing the seconds hand. Just a quick sketch below to illustrate. In practice, I'll drill oversize, fit the oversize plug, then turn down the pivot and burnish to finish. When all done the repair is invisible.

[Sjk4x4]

You are totally right, I am mistaken in what I was thinking was the bearing surface. Noob mistake.

11 hours ago, nickelsilver said:

As JDM said, those marks are a remnant from cutting e a stepped plug, so that there is a bit of a shoulder at the pivot/pinion interface so that the pivot doesn't pull out when removing the seconds hand. Just a quick sketch below to illustrate. In practice, I'll drill oversize, fit the oversize plug, then turn down the pivot and burnish to finish. When all done the repair is invisible.

Thank you for your "Quick Sketch" Mine would have been unintelligible by comparison. I will do the repair as you've illustrated. I was concerned about how small the arbor was going to be at first. Your repair is the superior method