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Do I glue this jewel back in????


LittleWatchShop
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Working on a Waltham P75MJWC movement.  All was well until I put the center wheel bridge in.  The jewel just fell out.

Do I glue it in?  What kind of glue?

2021-07-02 22_30_34-IMG_7352.JPG ‎- Photos.png

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Hi Texas,     I lay the bridge on an anvil and make four nicks around the premiter of the hole, be careful not to bend the bridge.

Good luck pal

 

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Several options according to your skill and equipment.

Close the hole with a domed punch, then ream if necessary

Tin the hole with solder then ream

Loctite 638 gap sealant

SLO-ZAP gap sealant (CousinsUK)

Jewellers cement

And of course shellac - make a thick solution in alcohol. This is the easy fix and it is reversible.

 

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There are two jewels here. I'm guessing when you installed the bridge the center wheel wasn't seated in its jewel, pushed up, and knocked out the upper jewel (it's for the 4th wheel). I would try pressing it back in; but first, push out the other jewel. Then press each one in from its side, making them just-flush with the surface. They aren't supposed to touch each other.

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The correct way is to close it with the correct punch. Those jewels are only press fit. 

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If the bridge would be of brass I would recommend to close it with a punch since the material is so soft the jewels would widen the hole when they go in and they wouldn’t stay in place when pushed in again, but if it is a harder alloy like nickelsilver or steel I would just push them back in as @nickelsilver suggests. One sometimes has to asses what material is holding the jewel.

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Great input! I will take a careful look this morning and report back. 

I have staking sets and jeweling tools, so all I need is to apply best method.

this watch has never been serviced...pretty sure. 

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OK, here is the big (little) picture.

As you can see, there is a place for only one jewel.  It sits on a recessed rim.  The jewel sits top side.

I think the jewel is providing a bearing surface for the sweep second wheel.

Sooo, I think that I do nothing special.  Place the bridge, place the jewel, drop in the sweep second wheel (et al.) and install the train plate.

BTW, these pictures were taken on my stereo microscope.  Only yesterday I designed an interface between the eyepiece and my old Canon S95 camera (3D printed converter). Wow...my new tool appeared just in time!

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2021-07-03 06_27_09-IMG_7370.JPG ‎- Photos.png

2021-07-03 06_26_51-IMG_7371.JPG ‎- Photos.png

2021-07-03 06_26_39-Photos.png

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Posted (edited)

Does look like two jewels.  lots of good advice.  Could close the hole or find a new jewel and retap the hole to fit only 1 jewel.  I would make a setting:)

Edited by jdrichard
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9 hours ago, jdrichard said:

I would make a setting

Yes you would.  I have seen your work...I am not there yet.  This is watch came from the pile...using it to learn but not ready to learn jeweling.  I have all the tools to do it I think...Dad left me a lot!

 

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Not sure what sins I committed to receive the punishment I got today.

This P75 presented yet another jewel issue.

The shock jewels are MT Antichoc.  They suck big time.  They come out in three pieces, hole jewel, cap jewel, spacer.  SPACER!! Really?  And I was not paying attention as to order and orientation (I am still a noob 😞 ).  Moreover, the spring on the bottom jewel can easily disconnect (and fly away).  The top jewel spring is blocked from escaping by the regulator ring.  Well...I was assembling the jewels wrong and could not get the springs to engage. Finally posted for help on a FB watchmaking forum and got an instant answer.  Still...with the true knowledge, it was a very challenging task.

All of my work was done inside a baggie.  Thankfully so, because that spring went flying five or six times.  Jewels too.

It is all together now but I am not happy with the readout on the timegrapher.  This is part of my training...figure this stuff out.

2021-07-03 12_23_37-IMG_7348.JPG ‎- Photos.png

2021-07-03 12_30_38-Photos.png

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On 7/3/2021 at 1:35 PM, LittleWatchShop said:

As you can see, there is a place for only one jewel.  It sits on a recessed rim.  The jewel sits top side.

While I had the Lorsa P72 case back open I thought I take a couple of shots to show how the bridge should look like. As you see the Lorsa P72 and the Lorsa P75 are quite the same with small tweaks separating them. (Yes, I already took the click away).

1_Movement.thumb.jpg.09186ff5a882a7dd6c1ef79269e51249.jpg

 

Here we see the Lorsa logotype, same as in your Waltham.

2_Logo.thumb.jpg.d6674e6f889d652ef77825f675211103.jpg

 

We fast forward a bit to get to the lower bridge. Here it is with its upper jewel.

3_Bridge.thumb.jpg.15710f927dfea416221ccee16898ebf3.jpg

 

The upper jewel is slightly smaller with a small hole in it to guide the second wheel, it also has an oil sink.

5_Lower_Jewel.thumb.jpg.975a445e249f03bc6a9b6d8e7e3a6129.jpg

 

The lower jewel is larger one with a large hole to guide the center wheel, this one is just flat.

4_Upper_Jewel.thumb.jpg.6d840713993b9225371a4cf51d3893e2.jpg

So, two jewels and if you found them you should be able to just press them in flush with the bridge, no extensive
work or quirky ideas needed.

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10 minutes ago, HSL said:

The lower jewel is larger one with a large hole to guide the center wheel

I am virtually certain there was no lower jewel on the P75.  I check to see how the center wheel interfaced to the plate and it appeared to be metal-metal.  Furthermore, odds of two jewels being loose and falling out seem pretty low.  A real mystery.  Thanks for taking the time to take the pictures.

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