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Too much end shake here?

fellerts
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fellerts Watch Enthusiast

fellerts

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Hi guys,

I'm attempting to service an AS 1703 movement these days. It wasn't running when I got the watch, and I think the problem is excessive end-shake on the escape wheel. I'm attaching a picture of the train with the bridge to provide some context here.

IMG_3155.thumb.jpg.9df2ba956a3db8dabb3927eff11a0a0d.jpg

In these next two pictures I show the escape wheel pinion as seen from the escapement in its two extreme positions.

IMG_3158.thumb.jpg.596e5cfdec601e210d97ae6e85c63611.jpgIMG_3157.thumb.jpg.3e1742c6d21a6693fd659211c52af835.jpg

The issue seems to be that when the escape wheel sits as far into the main plate as it will go, the pinion meshes with both the third and the fourth wheel, causing a lockup. I've checked the escape wheel bearing jewels and they look spotless. The wheel itself also looks good in my opinion:

IMG_3175.thumb.jpg.8449e7fbee451947c152e8133e181dcc.jpg

My question is this: do you think my assessment is reasonable, and would the solution be to shift the bottom bearing jewel slightly up? I don't own a jeweling tool so I can't hope to fix this anytime soon, but I would like to know to (in theory) fix this 😄

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watchweasol Distinguished Member

watchweasol

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Hi Your theory sounds plausible. When the escape wheel is in its upwrd position it runs ok , yes    and in the lower position it catches the fourth wheel , Yes, then the only recourse is to move the lower jewel up  to limit the end shake . or try another escape wheel with a narrower pinion.  Is the escape wheel an original or a replacement. As you received it as a non there is always the possibillity that's the reason it did not work in the first place.

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fellerts Watch Enthusiast

fellerts

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On 11/10/2022 at 10:37 PM, watchweasol said:

Hi Your theory sounds plausible. When the escape wheel is in its upwrd position it runs ok , yes    and in the lower position it catches the fourth wheel , Yes, then the only recourse is to move the lower jewel up  to limit the end shake . or try another escape wheel with a narrower pinion.  Is the escape wheel an original or a replacement. As you received it as a non there is always the possibillity that's the reason it did not work in the first place.

Thanks watchweasol. I have no idea about the service history on this watch or if the escape wheel is original. Maybe I will be able to fix this one day, but that day is not today...

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fellerts Watch Enthusiast

fellerts

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1 hour ago, nickelsilver said:

Can you post a pic of the dial side? Your escape wheel has a conical pivot on the lower side, which means it should work with a cap jewel. If the cap jewel is missing, or if the wheel was replaced with one needing one, it would cause exactly the issue you are seeing.

Well spotted, the escape wheel did have a cap jewel which I had removed for cleaning and promptly forgot all about. I didn't know about conical pivots and that they are supposed to ride on the cap jewel! Of course, replacing the cap jewel solved the issue and the end shake is now much more reasonable. No more binding!

I feel like a fool now, but at least I learned something new 😄 I owe you a beer @nickelsilver!

IMG_3218.thumb.jpg.4c3b3bf93b400e91f85a7ff1f9f652d8.jpg

I'll update this thread if I manage to get this running again. Still not sure why it wasn't running before, though my bet now is simply because it was very dirty.

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fellerts Watch Enthusiast

fellerts

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Update: It did run with eventually, but with very low amplitude. Then I noticed that the top escape wheel pivot was bent. I tried carefully bending it back and it snapped of course. Since I bought this for practice I'm not too bummed, though I'm not sure whether I bent the pivot or if it was bent from earlier. I'll inspect more carefully when disassembling in the future.

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