In situ remedy for worn 3rd wheel bushing?

[mbwatch]

Hi all - I am working on a 12 size, 7 jewel Waltham movement and have overcome several different issues with it already. One of the last I can see now is the upper 3rd wheel bushing is very worn and egg shaped. It isn't stopping the watch but the side shake is enormous at probably 25% the width of the pivot, it can't be helpful.

Is it possible to stake a hole like this closed then broach it back into round, or is the only real fix to replace the bushing? This looks like it is pressed in rather than milled into the barrel bridge and I do have a donor where the 3rd wheel bushing is less worn, but it's the wrong color (gilt). No lathe available.

No microscope, so this is the best I can capture:

Edited July 28, 2024 by mbwatch

[nevenbekriev]

Looking at thre picture, I doubt there is bushing there at all. Seems like it is just stamped. If there is a bush, then the best decision is to replace it. Another simple option is to mark the bush position, to press it out and then return in place but rotated to 180 degr. Thus the wheel position will be restored. Oil retention then may suffer, but using grease like 8200 will solve the problem.

Punching to close the holle is possible, but it will change the wheel position and will spoil the look. Actually, spoiling the look here is the main danger in such repairs. One option is to fit thinny bush wit only slight enlarging the hole. The hole is to be elarged and blunted with tappered pin from the down side, then the pin cut and made flush with down surface, then new hole drilled in correct place. Then the upper, visible side of the pin has to be trimmed by slightly bigger drill bit or turned on the lathe with face plate and finally slightly punched with polished  round tipped punch to form the top side and in the same time riveting the bush. Then final opening of the hole with smoothing broach... This technic alows to make the bush almost invisible. The other option is to drill the whole thing and fit new pressed bush, but keeping the center unshifted can be a chalenge.

I

[CYCLOPS]

also make sure the pivot on the third wheel is not mushroom shaped/worn.....

[rjenkinsgb]

Is it one of the Waltham movements that was made with various numbers of jewels? It may be that the plate is cut to take either the brass cased jewel or a simple bush?

If that is the case, you could swap the bush for one from a donor, or even fit a jewel type insert if the pivot diameter is appropriate?

I wonder if the bush & jewel inserts are the same size across movements? That would make sense for mass production?

 

[Neverenoughwatches]

I will be interesting to see if this is a separate pressed in bearing or part of the plate itself . If the plate then accurate drilling of the correct hole position without a lathe and centering equipment....... that wont come easy. Once the hole is oval-shaped good skill with the right tools becomes necessary.  Curious as to Nev's way of filling in the hole with a tapered pin and create new hole ?

[rjenkinsgb]

I am very curious whether you can press out a bush from the donor movement you have, if that is definitely not going to be restored? 

However, just examining the plates on the 16s donor movement I have, it does appear the non-jewel positions are just machined directly in to the plates, and are smaller diameter than the inserts in the jewelled version.

 

[mbwatch]

6 hours ago, nevenbekriev said:

Another simple option is to mark the bush position, to press it out and then return in place but rotated to 180 degr. Thus the wheel position will be restored. Oil retention then may suffer, but using grease like 8200 will solve the problem.

This is a very interesting workaround. Because I have no machines and experience with the precision techniques you described to produce a new invisible bush, I will try the 180° rotation if it can be pressed out. Thanks for all your valuable information!

 

3 hours ago, rjenkinsgb said:

I am very curious whether you can press out a bush from the donor movement you have, if that is definitely not going to be restored? 

I'll make time to try and push it out tonight. I have worked on a lot of 7j movements where the underside of the plate just had pivot holes directly in the plate and were therefore definitely not pressed in. But this one has a ring around the underside making it look like it could be a separate bush. I also wondered about a jeweled setting from another similar grade, but then I think since those are usually lightly pushed in and screwed down rather than friction fit, they would not be the same size. They also usually have a ridge or step on the underside, exposing a smaller hole on the plate bottom than on the top. In any case, this is a Waltham grade 210 which seem to have been very common. Donors are in abundance.

4 hours ago, CYCLOPS said:

also make sure the pivot on the third wheel is not mushroom shaped/worn.

I will check, but I don't have a Jacot tool to fix it. I would have to find a donor wheel that is not similarly damaged.

 

3 hours ago, Neverenoughwatches said:

I will be interesting to see if this is a separate pressed in bearing or part of the plate itself

Yeah, I'll try to push one out of my donor and report back. From the underside, it also looks like it was pressed in.

[SwissSeiko]

This looks like the perfect excuse to get a lathe! Then you could press out the bushing and make a new one.

[mbwatch]

@nevenbekriev @Neverenoughwatches @rjenkinsgb It is indeed a pressed in bush. I pushed one out of my donor's train bridge. There's a decent chance I will be able to find a direct NOS replacement, since the American watch companies produced spare parts in huge numbers.

Furthermore, I was just looking over other Waltham 12s movements and they do use pressed-in jewel settings on the train. Unlike Elgin & Illinois I'm more experienced with, who used the non-friction fit settings fixed down with screws. So theoretically I could replace this with a jewel from another donor, but then I'd want to upgrade the whole thing to 15 or 17 jewels and I might as well just restore the jeweled donors instead.

Edited July 29, 2024 by mbwatch

[CYCLOPS]

You need a staking set, that's all for this......it will last a lifetime 

[mbwatch]

4 hours ago, CYCLOPS said:

You need a staking set

I have one! That was part of my question originally. Can a small wheel pivot (as opposed to a large barrel arbor hole) be feasibly staked back into round. Though I will need to buy smaller broaches if I do it that way. I believe my smallest smoothing broach is 0.40mm. But I also did find a NOS source to buy and relevant documentation on these bushings.

[CYCLOPS]

Like some have said earlier, you can close the hole and broach to size with the staking set and proper punches, but the marks that are left showing don't look nice and match the other bushings, plus as said before sometimes the hole can get off center causing the wheel to not run truly upright, donors or your source are the way to go in my opinion.....

[rehajm]

I’ve closed holes like this in cheap movements with success- from snow to rails on the tg, but it’s a dent and there’s a certain amount of luck just broaching. It’s a bodge job, really…

Glad you have other options…

[mbwatch]

I closed the hole with my smallest round punches and it came out well. There is no visible evidence of the repair on top side unless examined under a loupe if you know what you're looking for. The underside has an indentation and I thought it might affect the end shake but that didn't change. It did take me three tries to broach it to the right size; I overdid it twice. But this was for practice, knowing I could still get a NOS replacement. Happily, the sideshake has been eliminated and the wheel spins free and true.

[nevenbekriev]

6 hours ago, mbwatch said:

Happily, the sideshake has been eliminated and the wheel spins free and true.

If the wheel is OK, then it always will turn true. It doesn't depend on the bearings position. But if the bearing is shifted, this will affect the depth of mesh with the neighbor wheels. Small shifting (this is the case here) has not that significant effect

[CYCLOPS]

I am glad it worked out, the cosmetic look was what I was trying keep, bushings are cheap and or easy to get and replace, I have closed many on clocks too....