Bulova Rubaiyat 1920/21

[GPrideaux]

I have an early Bulova wristwatch that I hope to be able to get going. It was an eBay purchase which I bought out of historical interest. I'm interested in Bulova watches principally because the first watch I successfully repaired was a Bulova that I'd bought for myself.

The watch offers me a number of challenges, some of which I think I'm ready for; others not so much.

When I first opened the watch I noticed two things immediately: there was oil everywhere, and the balance wheel looked bent.

Ok, I'll remove the balance from the cock and then disassemble the movement and clean it while I see what can be done with the balance. First challenge: there is no screw for the stud. How to remove it? I've already had some assistance with that in this thread. Opinions were divided whether to push the stud out or unpin the spring from the stud. I pushed it out. (There's also some information in that thread about my fruitless attempts to put a number or code to the caliber.)

I took a square-on photo of the balance so I could superimpose a circle to see just where it began to be out of round, then cautiously began to manipulate it, gently pulling up the side that had been bent it. As soon as it came clear of the point where the two ends crossed (in the right of the photo above), the balance sprang back into shape. I'd been catastrophising that I'd struggle to get it in anything like good poise but now it looked like it might be already there. Phew.

The hairspring will need a little adjustment ... it looks to have been a little bent at the regulator, but I think I can deal with that later.

Next, attempting to let down the mainspring gave some difficulty. Initially the crown would not turn at all, then I realised it was in the hand setting position. Why that resisted the crown turning is an issue for later. Pushing it in to winding position allowed it to move a little, but it seems the mainspring was fully wound and I could not move the ratchet wheel enough to release the click. In the end I removed the pallet while holding the train wheels so they could not unwind catastrophically. I wasn't too worried, as I'd already determined that there was little to no power coming through to the pallet. Even with it removed it was only by working wheels forward and backward that I could unwind the mainspring enough to be able to release the click and unwind the rest of the spring through the crown. Removing the train bridge revealed an oily clump of fibres caught in the train.

Inspecting the pallet revealed a lack of shellac on one side. I discussed that a little in this thread. The jewel on that side is not quite straight.

It also looks like the guard pin is bent, but I don't think that's actually a problem. When I inspected it under my stereo microscope I found the pin parallel to the horns of the fork in the vertical plane, as it should be, and the top of the pin centred between the horns of the fork. I believe it looks bent because the base of the pin is off-centre but as it's the tip of the pin that is important I don't think that matters.

The next challenge, and probably the greatest one, was encountered when disassembling and inspecting the jewels. First I noticed the pallet jewel:

Ugh. I'd love to be able to clean that up, but the chance of my doing so successfully without damaging the jewel? Not worth it just for the aesthetics of it. I checked that the pallet sits properly in the jewel and although end-shake is a little high it seems it's probably going to be acceptable.

But then I saw the escape wheel lower jewel:

The rest of the jewel came out in the ultrasonic and seems to have vanished, and in the process it seems to have slightly damaged the feathered edge for the rubbed in setting. This leaves me stumped. I don't have the tools to open and re-burnish a rubbed-in jewel, and I can't find where to get them. I can make a tool to open the setting, I think, but closing it again will be more challenging. Even if I had the tools, however, where can I get the jewel to go in there? From what I've read, rubbed in jewels have a different shape from friction fit jewels.

It seems to me that it may be more productive to replace the rubbed-in setting with a friction fit jewel. I'm not worried about it making the movement less original (especially given that it'll be hidden away on the dial side), but I'm not sure how to go about it, either. Some of my reading suggests that it might need a bushing made. I don't have a lathe, and any such acquisition is likely over the horizon for me, so if that's what's going to be needed then I'll have to do the bits I can then shelve the project for now.

While meditating on the escape jewel I thought I'd just check how the balance sits between plate and cock: not well. After a first attempt where the pivot kept coming out of the jewel as I was trying to fasten the cock I tried the cock by itself, and it does not sit parallel to the plate but rises at the end. Trying again with the balance wheel I confirmed that the balance end shake is so great that the pivots can come right out of their jewels. The cock is bent and will need to be bent back into place. Another thing I'm not sure how to do. I presume I shouldn't just hit it with a hammer.

[nevenbekriev]

First focus on escape wheel jewel.

First take a look at this video

Of course, everything is possible without special tools here. But yes, replacing the setting for bushing with press-fit jewel is possible and is good option too. I will need better photo of the jewel hole now, as what I sow in the other thread is little bit frightening as the hole may be ruined already.

[Neverenoughwatches]

  On 12/29/2024 at 2:37 PM, GPrideaux said:

I have an early Bulova wristwatch that I hope to be able to get going. It was an eBay purchase which I bought out of historical interest. I'm interested in Bulova watches principally because the first watch I successfully repaired was a Bulova that I'd bought for myself.

The watch offers me a number of challenges, some of which I think I'm ready for; others not so much.

When I first opened the watch I noticed two things immediately: there was oil everywhere, and the balance wheel looked bent.

Ok, I'll remove the balance from the cock and then disassemble the movement and clean it while I see what can be done with the balance. First challenge: there is no screw for the stud. How to remove it? I've already had some assistance with that in this thread. Opinions were divided whether to push the stud out or unpin the spring from the stud. I pushed it out. (There's also some information in that thread about my fruitless attempts to put a number or code to the caliber.)

I took a square-on photo of the balance so I could superimpose a circle to see just where it began to be out of round, then cautiously began to manipulate it, gently pulling up the side that had been bent it. As soon as it came clear of the point where the two ends crossed (in the right of the photo above), the balance sprang back into shape. I'd been catastrophising that I'd struggle to get it in anything like good poise but now it looked like it might be already there. Phew.

The hairspring will need a little adjustment ... it looks to have been a little bent at the regulator, but I think I can deal with that later.

Next, attempting to let down the mainspring gave some difficulty. Initially the crown would not turn at all, then I realised it was in the hand setting position. Why that resisted the crown turning is an issue for later. Pushing it in to winding position allowed it to move a little, but it seems the mainspring was fully wound and I could not move the ratchet wheel enough to release the click. In the end I removed the pallet while holding the train wheels so they could not unwind catastrophically. I wasn't too worried, as I'd already determined that there was little to no power coming through to the pallet. Even with it removed it was only by working wheels forward and backward that I could unwind the mainspring enough to be able to release the click and unwind the rest of the spring through the crown. Removing the train bridge revealed an oily clump of fibres caught in the train.

Inspecting the pallet revealed a lack of shellac on one side. I discussed that a little in this thread. The jewel on that side is not quite straight.

It also looks like the guard pin is bent, but I don't think that's actually a problem. When I inspected it under my stereo microscope I found the pin parallel to the horns of the fork in the vertical plane, as it should be, and the top of the pin centred between the horns of the fork. I believe it looks bent because the base of the pin is off-centre but as it's the tip of the pin that is important I don't think that matters.

The next challenge, and probably the greatest one, was encountered when disassembling and inspecting the jewels. First I noticed the pallet jewel:

Ugh. I'd love to be able to clean that up, but the chance of my doing so successfully without damaging the jewel? Not worth it just for the aesthetics of it. I checked that the pallet sits properly in the jewel and although end-shake is a little high it seems it's probably going to be acceptable.

But then I saw the escape wheel lower jewel:

The rest of the jewel came out in the ultrasonic and seems to have vanished, and in the process it seems to have slightly damaged the feathered edge for the rubbed in setting. This leaves me stumped. I don't have the tools to open and re-burnish a rubbed-in jewel, and I can't find where to get them. I can make a tool to open the setting, I think, but closing it again will be more challenging. Even if I had the tools, however, where can I get the jewel to go in there? From what I've read, rubbed in jewels have a different shape from friction fit jewels.

It seems to me that it may be more productive to replace the rubbed-in setting with a friction fit jewel. I'm not worried about it making the movement less original (especially given that it'll be hidden away on the dial side), but I'm not sure how to go about it, either. Some of my reading suggests that it might need a bushing made. I don't have a lathe, and any such acquisition is likely over the horizon for me, so if that's what's going to be needed then I'll have to do the bits I can then shelve the project for now.

While meditating on the escape jewel I thought I'd just check how the balance sits between plate and cock: not well. After a first attempt where the pivot kept coming out of the jewel as I was trying to fasten the cock I tried the cock by itself, and it does not sit parallel to the plate but rises at the end. Trying again with the balance wheel I confirmed that the balance end shake is so great that the pivots can come right out of their jewels. The cock is bent and will need to be bent back into place. Another thing I'm not sure how to do. I presume I shouldn't just hit it with a hammer.

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Lol hitting with a hammer is the final emotion when nothing else works...even that isn't acceptable,because...well everything in watchmaking is useful...eventually . The most difficult job first which is the escapewheel jewel. If that cant be accomplished then all the other work is just an exercise.  

[GPrideaux]

It won't surprise me if the hole is already ruined, and it may not be all my doing. All the jewel settings on the plate have been crudely countersunk.

Balance jewel:

Pallet jewel is the most obvious:

Escape wheel where the jewel is missing still shows signs of having been countersunk which is why it's so thin and out of round at the edge:

Fourth wheel:

Third wheel:

There's also some butchery presumably to create adjustable banking pins:

Clearly someone has put quite a lot of work into this plate. I wish I could be confident they knew what they were doing.

The dial side of the plate looks untouched:

The balance jewel is red so likely not original. Is it still rubbed in or has a friction fit jewel been used? I can't tell.

The pallet jewel:

What remains of the escape wheel hole. The feathered edge is somewhat chewed up. It looked ok before it went into the ultrasonic but when I came to try to open it up it already had cracks.

Fourth wheel:

Third wheel:

 

@nevenbekriev, I loved the video: very helpful. However all the donor movement parts I have use friction fit jewels so I don't have anything I can harvest a suitable jewel from.

Side note: I don't have ANY spare jewels. Cousins do a jewel assortment of 1000 hole and cap jewels for £9.95. What are opinions on that? Is that likely to be useful, or will I just have 1000 jewels all the wrong size whenever I need one?

[Neverenoughwatches]

Such a lot of countersinking to all the jewels, very strange. I'm thinking a lot of these jewel settings are pressed in and some are rubbed-in jewel settings. As regards to the 1000 cousins jewels, I bought the same vial of jewel off Ebay. About half of it was rubble and bits of metal, discarded,defective and damaged jewels. I sorted all the ok stuff, measured it up and added it to stock. If you use just one jewel from it, you will just about break even.

I think its basically just floor sweepings.

[nevenbekriev]

Modern friction fit jewels can be used as rubbed in, but some preparation of the jewel is needed. At least one of the edges needs to be rounded as to allow the collar to lay and fix the jewel. For this purpose, the jewel must be glued on the face of thin rod (thin as the jewel OD). Then the edge is to be ground on diamond disk or plate while the rod is rotated by hand.

The hole for the jewel seems still usable

[GPrideaux]

  On 12/30/2024 at 5:59 PM, nevenbekriev said:

Modern friction fit jewels can be used as rubbed in, but some preparation of the jewel is needed. At least one of the edges needs to be rounded as to allow the collar to lay and fix the jewel. For this purpose, the jewel must be glued on the face of thin rod (thin as the jewel OD). Then the edge is to be ground on diamond disk or plate while the rod is rotated by hand.

The hole for the jewel seems still usable

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Thanks, I'll have to experiment.