Pocket watch barrel bridge and barrel disassembly

[Klassiker]

I am trying to get an old pocket watch running for a neighbour of mine. It has Louis Eschholz Gotha inscribed in the case, which would make it easily 100 years old. As you can see, there is a key for winding and setting. Here's the partially disassembled movement, still in the case until I worked out how to remove it. It's got a cylinder escapement, so there was an exciting moment when I removed the balance.

What would have been the correct let the mainspring down?

Luckily no damage was done, so I got everything stripped down completely except for the barrel and bridge assembly. Any suggestions how I should proceed? Unfortunately the stop work is incomplete.

 

 

 

[oldhippy]

I'm off to bed now. I'll give you the answer tomorrow. 

[MrRoundel]

It may have a two-piece barrel-arbor. That means that in order to remove it from the bridge, you must unscrew the sides of the arbor. That's what I had to do do on a Vacheron that I worked on recently.

When oldhippy wakes up, he may tell you that the arbor has left-handed threads, so be careful, and don't proceed until you know. You can snap the square off the arbor. Sorry to say, but I have done it.

If you indeed got as lucky as you think you did when you pulled the balance, it was probably because there was very little power left in the mainspring. All's well if it ends well. Good luck with the watch.

Edited July 16, 2019 by MrRoundel
Typo correction

[HSL]

Today I was an early bird and took some minutes to disassemble a bridge like yours.
I let the pictures speak for them self since there is not that much to comment.
One can like me be lazy and use a wrench as an vice, I also uce a circle to unscrew the nut part of the barrel arbour.
Hope this helps you...
 

[oldhippy]

The correct way would be to let the power down with the correct size watch key, by moving the click away from the ratchet, that is located under the little plate, held by the tiny screws. Always remember with a cylinder escapement there are no pallets, so power must be released first before any attempt is made removing the balance.

So you have the barrel and the bridge all together. Remove the barrel cape and remove the spring. The barrel arbor should unscrew and become two pieces, and then it will come away from the bridge. Many are not easy to take completely apart, if you find this my advice would be to clean it as it is, you do not want to damage the arbor. You have the thin plate off which exposes the ratchet, that is the part that is going to be the most dirty part and underneath.

I cannot remember which way the arbor unscrews. Its over 25 years ago for me. Not all arbors have the two holes as in the diagram above. so be careful. 

[HSL]

Just got to think about it when I read the part of letting  the power down, these movements have a stop function in the winding.
If you just let the barrel go in an uncontrolled way you might break the stop finger. I often find these ratteling in the watches from now and then, and I can't see it in your picture of the barrel bridge either.
 

[vinn3]

good show,  you did good by not removing the balance till the main spring was let down.  "no pallets in this design!"   a watch "with pallets"  it is proper to remove the ballance before spring let down.   keep up the good work.   vin

[Klassiker]

5 hours ago, vinn3 said:

good show,  you did good by not removing the balance till the main spring was let down

No, I did not do good! I did very bad, but got away with it thankfully, as it's not my watch. Lesson learned. Look before you leap and all that. Thanks for the encouragement!

[Klassiker]

Quote

12 hours ago, HSL said:

Today I was an early bird and took some minutes to disassemble a bridge like yours.
I let the pictures speak for them self since there is not that much to comment.
One can like me be lazy and use a wrench as an vice, I also uce a circle to unscrew the nut part of the barrel arbour.
Hope this helps you...
 

 

That is (almost) identical to the part I have. Could not have wished for better support, thank you! I do not have the two holes in the barrel arbour, so I can't use a compass or similar to unscrew it. I will try gripping the circumference with something. The action of the spring suggests it is a conventional right-hand thread, correct?

11 hours ago, HSL said:

Just got to think about it when I read the part of letting  the power down, these movements have a stop function in the winding.
If you just let the barrel go in an uncontrolled way you might break the stop finger. I often find these ratteling in the watches from now and then, and I can't see it in your picture of the barrel bridge either.
 

Part of the stop-function (the disc with the finger on it) was missing when I opened the case, so it may well have been broken by another bodger who got there before me. I have the Maltese cross part. I may have a go at making a replacement if it's not too difficult. Would you have a picture of the part I need? How is it held in place?

[Klassiker]

17 hours ago, MrRoundel said:

It may have a two-piece barrel-arbor. That means that in order to remove it from the bridge, you must unscrew the sides of the arbor. That's what I had to do do on a Vacheron that I worked on recently.

When oldhippy wakes up, he may tell you that the arbor has left-handed threads, so be careful, and don't proceed until you know. You can snap the square off the arbor. Sorry to say, but I have done it.

If you indeed got as lucky as you think you did when you pulled the balance, it was probably because there was very little power left in the mainspring. All's well if it ends well. Good luck with the watch.

Thanks for the encouragement. I think it has to be a right-hand thread on the arbor, due to the direction the spring is acting. The mainspring did indeed have quite a bit of power left in it. There was a buzzing and a whirring for quite a while after I pulled out the balance, so it seems I have been very lucky indeed! I will check everything carefully again for damage. I have already found one cracked jewel.

[MrRoundel]

Good job. That was smart using that compass(?) for a "special wrench". I can't remember what I used. It might have been a junky set of tweezers. I'll remember the compass-tool.

Bob Tascione has a nice animation of the workings of the stopworks. In it, you should be able to see the shape of the part you need. It's on youtube. Search his name and you'll find it. Good luck.

[HSL]

Glad I could help a little bit and Yes it's is a ordinary right hand thread on them.
It's quite common those are missing, as a fact I looked for one for a IWC 66 a while but ended up making one.

If you look a the sqare stem you will find a small hole in it, it's where you put a thin pin in to lock the finger piece into place.

[vinn3]

10 hours ago, vinn3 said:

good show,  you did good by not removing the balance till the main spring was let down.  "no pallets in this design!"   a watch "with pallets"  it is proper to remove the ballance before spring let down.   keep up the good work.   vin

     no problem; keep going, you are learning to hate that type of escapment.  vin

[Klassiker]

22 hours ago, HSL said:

Glad I could help a little bit and Yes it's is a ordinary right hand thread on them.
It's quite common those are missing, as a fact I looked for one for a IWC 66 a while but ended up making one.

If you look a the sqare stem you will find a small hole in it, it's where you put a thin pin in to lock the finger piece into place.

Many thanks once again HSL! It looks like making one may be beyond me, but I will have a go and report back. The square stem does indeed have a hole for a pin. Some of the pin is still in there!

[Poljot]

On 7/16/2019 at 2:47 AM, HSL said:

Today I was an early bird and took some minutes to disassemble a bridge like yours.
I let the pictures speak for them self since there is not that much to comment.
One can like me be lazy and use a wrench as an vice, I also uce a circle to unscrew the nut part of the barrel arbour.
Hope this helps you...

I am not here to judge your tools selection as I used the same "professional set"

However, I believe your comments above "split the barrel arbour" and "the gear is friction fitted and can be pressed out" maybe misleading. At least in my case, it was a screw-in two part arbour, not press fitted. And there was no way I could split the arbour as those two holes are ... just two holes...