Best way to proceed with jewel

skinnb1

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I am an inexperienced amateur with reasonable experience with clocks but now I have a pocketwatch. Before I do anything irreversible I am looking for some guidance on how to proceed.

The watch has a Swiss cylinder movement from around the end of the 19th century.

I have dismantled, cleaned, re-assembled and lubricated the watch and it runs but only dial down. As soon as I raise it from the bench to examine the dial it stops. I am thinking that the problem lies with the balance cap jewel which appears to have a long scar. The hole jewel looks OK.

The first question is: Is my diagnosis of the problem likely to be correct? If so and I want to replace this jewel does that involve finding a jewel of the correct size, pushing the old jewel out of its setting, opening the chaton, and rubbing in the replacement jewel.

This sounds difficult, but I'm prepared to go ahead if this seems the correct thing to do.

Thanks for looking.





210707172805176083906.jpg 210707173215176334593.jpg 1625676671991.png
 

gmorse

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Hi skinnb1,

Have you confirmed that the balance staff top pivot is still intact? These cylinders often suffer from broken pivots and that jewel could have been damaged if the pivot is indeed broken. The pivots in Swiss cylinders are on plugs, ('tampons'), which are friction fitted into each end of the cylinder, and spares assortments are still available on eBay from time to time, but without a lathe, (and preferably also a Jacot tool), they are difficult to fit and bring to size.

The jewel can certainly be replaced, more or less as you describe, but these rubbed-in jewels are no longer made and you may find it hard to source a replacement of the correct size. The modern Seitz friction jewels won't necessarily fit in that setting.

Regards,

Graham
 

Brunod

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Jun 8, 2021
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Both pivots should have the same length. If you look only one and are not used to, it might seem ok but comparing with the other it shows one is obviously shorten / broken. From my own experience, except when replacing the full cylinder with both pivots allready "pivoted", you allways have to use a jacot lathe to finish the tampons and pivote them so they fit in the jewel. Sometimes they are to long, but you may not smash them deeper in the cylinder anyway; use the jacot instead.
You need a cylinder bank with punches too.
1625681338350.png


I wish you a happy discovery :)

Edit : these were natural rubies stone, sometimes with default. If the default is on the outer side, it doesn't matter. On the picture, I can't see on which side the scar is.
 

gmorse

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Hi skinnb,

To add to the list of tools you need, something which Bruno hinted at is a special punch which reaches inside the cylinder and allows the removal of the tampon. These are cranked and known as 'knee' punches and can be used with a staking set or a split stake as he shows.

Knee_Punches.JPG

Bruno, by the way, your picture is just a thumbnail and too small and blurred to make out any detail.

Regards,

Graham
 

Brunod

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Well I took an old picture of mine from another forum, I can't get the original right now.
So here is another one from internet.
1625727398484.png
 

skinnb1

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Thanks very much both for the replies. I think you have saved me from future pain.

I think I need to leave this alone for the moment. I imagine that the jewel and pivots were damaged at the same time. I have a watchmakers lathe with a Jacot attachment and a staking set but don't think I have all the tools required never mind the skills needed.

I have looked afresh at the pivots and they are certainly not the same length and the top pivot looks slightly bent. It nevertheless runs dial down.

I can get cap jewels from scrap movements but finding the correct size would be a challenge.

It's a shame as the silver case, the face and the rest of the movement are in good condition.

21070814003615857484.jpg
 

Brunod

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Well, seeing your picture, I'm not so sure one pivot is broken. But the inner side of the cylinder seems rusty or dirty at least.
You should check the end-shake to be sure. But good news : it doesn't seems that bad. Check the end-shake of the escapement wheel too. It might touch the cylinderat at wrong place and cause trouble too.
 

gmorse

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Hi skinnb1,

Well, the top pivot is certainly bent, and if it were me, I'd risk trying to straighten it, because it isn't going to work in this condition whether it's bent or broken. I'd remove the balance spring and set it up in the lathe, holding just the bent pivot in the appropriate sized collet, and then very gently ease it back straight whilst turning, (by hand, not under power!), a tiny amount at a time. This is a far gentler, controllable and safer method than the notorious 'hot pliers' or the Seitz 'pivot straightener' tool.

Have you got collets this small?

The pivot tips look flattened, which won't help, but they can be rounded up in the Jacot if you have the lantern plate, once you have a straight pivot again.

Regards,

Graham
 

Brunod

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There is a tweezer to straighten the pivot. Its a kind of flat nose, sturdy tweezer like this (but I'm not sure it is this one)
1625764270335.png


And there is a special Bergeon/Seitz tools therefore too.
1625763918434.png

1625764022932.png


And the last one is to round the top of the pivot, with a conical saphir inside
1625764538249.png
 

gmorse

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Hi Bruno,

If you can't afford to pay the outrageous price, (£606 in the UK), for the Seitz tool, you can break pivots for free just with stout tweezers! I have one but I only use it as a pivot gauge. I'll stick with the lathe method, it's safer!

Regards,

Graham
 

Brunod

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I don't own the special tweezers. I use brass tweezers. I never succeeded to straighten with the lathe but I didn't hold the pivot in the chuck. I use the jacot to finish/repolish the pivot after. To measure, there is a rubis gauge (but I prefer the JKA fine taster).
BD Seitz30150 2.jpg
 
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