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Disassembling a capped jewel


alexndr

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Hi guys and girls!

I have recently dug into a AS1730- movement. While putting the automatic winding assembly together I noticed that the bridge had two capped jewel holes. Looking at them through a microscope (pictures attached) one can clearly see that there are some fluid residing between the jewels and the caps. Probably fluid left from the cleaning? 

Now I need to know how to pop the assembly open to remove this fluid. Maybe I can push the entire assembly out with the staking tool or something, hoping for it to come apart? 

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I am not familiar with this jewel setup. From the pictures, it looks like the brass bezel has slots in it. Is it possible that this bezel is threaded into the bridge??? I would not recommend pushing on this unless you are certain as to the construction.

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Threaded? Hmm, maybe. There are some circular scratches around the bezel that could indicate it has been unscrewed with a screwdriver before? That would however require the bezel to be raised above the jewel (or some special tool to unscrew it). I can try to get a picture from a different angle of it.

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Never encountered those either, but the slot sure looks like it's meant to be screwed in/out. If you have something like the forked screwdriver for the "H screws" in Hublot watches you could try that, or just inserting the tips of a tweezer and twisting...

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Thanks for chippin' in guys! 

 

7 hours ago, StuartBaker104 said:

Have you searched on line for a tech sheet for the movement? I had a quick look, but AS1730 came up blank everywhere - are you sure that's right?

Sorry. You're right. It should be AS 1713. To late to edit the original post.

 

8 hours ago, Pip said:

I'll watch with interest, unfortunately I can't contribute. However, thumbs up for the images, they are exceptionally clear! What microscope / camera do you use?

I'm using an LCD USB microscope (https://www.cousinsuk.com/product/benchtop-digital?code=M39115). I had handheld versions of this before but it was not that practical to work with (required USB wiring to a laptop). The LCD screen is not great but it works. It has an SD memory card slot so it's easy to take photos and transfer to your computer. There is a lag between the optics and the screen so it's not possible to replace the loupe with it but for situations like this, it's awesome. 

 

1 hour ago, matabog said:

I'm not sure it's ment to be disassembled. I would use an IPA spray and an air spray (carefully not to blow the  cap jewel away)

That crossed my mind as well. I cleaned it in an Ultrasonic machine and rinsed with IPA. My ways of working for drying the parts has room for improvements since I have nothing more than a dust blower at hand.  I'll try air, or maybe heat, to dry it out. 

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That fluid has got to go and also it looks like some crud is in there as well. I have not seen this style of chaton but it certainly looks like it is a screw fitting.If it does not undo then maybe a good ultrasonic clean will shift the crud and if successful warm with a hairdryer to make sure all is dry & then lube using a auto oiler.

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19 minutes ago, rogart63 said:

Glue? Looks like somebody has glued the cap jewel? Maybe because they broke the incabloc spring? Just pop it out and replace with a new spring and a new jewel? 

While that's possible, I would proceed carefully. If those are indeed Incabloc Blocs, then you should be able to see where the slots are undercut to retain the lyre spring. Also - gluing would require quite a bit of care in order to prevent glue from entering the oil sump. It would, of course, also remove any shock protection. I would think someone capable of gluing those cap jewels in place would be capable of replacing a missing lyre spring. Not to mention that there are 4 of these settings. Seems unlikely to me, but anything is possible!

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1 hour ago, rogart63 said:

Glue? Looks like somebody has glued the cap jewel? Maybe because they broke the incabloc spring? Just pop it out and replace with a new spring and a new jewel? 

Struck me as well. The movement has definitely been serviced before. Some one has managed to mess up the crown wheel screw (it's left threaded, or at least it has been). Praying to higher instances that the bridge threading is not totally useless and that a new screw will do.  

1 hour ago, sstakoff said:

Alexndr - can you take another photo of the slot at a 45 deg angle???

I'll do it tonight. 

 

 

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Hard to get good photos but it seems that there are no slots for lyre springs. 

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Cap and bezel is in level so if it's a "screw fit" that would require some special tool (like the H- shaped screw driver suggested). I tried to turn it carefully with some dull tweezers but it wouldn't budge. 

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1 hour ago, alexndr said:
1 hour ago, Marc said:

Is it possible to see any evidence of threads in the bridge in the cut outs in the chaton?

No, I can't see any but they might still be there. 

I guess that would have been too easy :unsure:

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  • 2 weeks later...

I seem to remember that these were installed from the non-slotted side and the assembly peened over at the slots. When cleaning you just whack the whole thing out. This will damage the sides so you need to re-install so that the slots are in a fresh part of the hole.

If you measure the circumference of the slotted side and the none slotted side can you see a difference in diameter?

Anil

 

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