Train Wheel Bridge Reassembly

[ed1210]

I am pretty new to watch repair as a hobby, and am loving it so far. I've been working on some old Elgin pocket watch movements for practice.

I am wondering if anyone has any tips for the reassembly of the train of wheels and the train wheel bridge. I know this is probably one of the more difficult steps of reassembly. I am having a difficult time with the lining up of pivots on the bridge while keeping the wheels in their lower pivots.

Any advice for a newbie is very welcome!

Thanks!

Ed

[HectorLooi]

Practice, practice, practice. 

There is no substitute for actual hands on practice. It took me 45 mins to get the train bridge on when I first started. After 4 years of practice, I can usually get a train bridge on in under a minute.

There is no secret technique. Firstly, get all the bottom pivots into their respective holes and stand the wheels as upright as possible. Then take the top plate and orientate the holes to the pivots. Hover the plate just above the pivots and drop the plate on. If you are lucky, you'll get a "hole-in-one".  If not, try using the back end of your tweezer to tap lightly on the movement holder. The vibration may jar the pivots into their holes.

If all else fails, then you have to resort to the "poke and nudge" technique. Use your pegwood to apply gentle pressure on the top plate and use your tweezers to lightly upright the wheels and coax the pivots into their holes. Start with the bigger wheels first and work your way down to the escape wheel.

Sometimes with really stubborn ones, you might have to place some of the screws back in, but do not tighten them. They are placed only to prevent the top plate from separating and allowing the bottom pivots to get out of their holes.

Make sure you have good lighting, work at your shoulder level unless if you are using a microscope. Stay calm and breath slowly. Take breaks before you break something. 

Good luck and enjoy. 

[watchweasol]

I think Hector covers all bases ," just keep calm and carry on ".   I use the screw mothod as it retains the brigde and tappinf and shuffling usually works. The stubborn ones need a poke so I made some shaped tools from needles bent at various angles to get under the plate.

[ed1210]

Thank you both! It's actually reassuring to hear that it did take you a significant amount of time at first. And I like the needles idea to get under the bridge. I was trying with pegwood, but something much finer would be a good idea.

Thanks!

Ed

Edited April 18, 2022 by ed1210

[JohnR725]

On 4/18/2022 at 8:18 AM, ed1210 said:

Elgin pocket watch movements for practice.

Perhaps a picture might be nice? The reason I ask is if you are assembling a 18 size Elgin pocket watch the answer might be a little bit different than if it was a 16 size or a 12 size watch.

[ed1210]

Thanks. It is a size 16, here it is with the wheels in place and the bridge next to it.

[JohnR725]

When you're assembling the wheels you don't need to have the mainspring in their that can come out. Then the unfortunate reality is it's just a lot of practice. There is something you do want to check is put the plate on without the wheels how tight is that? Sometimes there are way too tight for going together and that can definitely be an issue when you're trying to figure out how to get your pivots in place because you won't have a good feel for things at all.

Otherwise unfortunately it just a practice technique thing. Usually helps to start at one side if there is a side or start with whichever wheel pivot manages to go in first and then work with the rest of them.

[ed1210]

Thanks again, all. It's reassuring to know that it is just a matter of practice. I appreciate it!

Ed

[ifibrin]

Some train wheels bridges fit more tightly into the main plate, especially if the movement has never been taken apart before. Before placing any of the wheels into the main plate it’s a good idea to get a feel for how tightly the train bridge fits onto the main plate, so that you know how much pressure you have to apply to get the train bridge to seat properly on the main plate. If you find that you need to apply a fair bit of pressure to get the train bridge to seat onto the main plate it’s probably best to take it off and put it back on a few times first, to make it less tight. Applying too much pressure into the train bridge during wheel assembly can cause broken pivots…

[ifibrin]

8 hours ago, JohnR725 said:

When you're assembling the wheels you don't need to have the mainspring in their that can come out. 

I have worked on some ladies movements where it’s quite difficult to slide the barrel in once the train bridge is on… but those tend to be tiny movements?

[HectorLooi]

23 minutes ago, ifibrin said:

Some train wheels bridges fit more tightly into the main plate, especially if the movement has never been taken apart before. Before placing any of the wheels into the main plate it’s a good idea to get a feel for how tightly the train bridge fits onto the main plate, so that you know how much pressure you have to apply to get the train bridge to seat properly on the main plate. If you find that you need to apply a fair bit of pressure to get the train bridge to seat onto the main plate it’s probably best to take it off and put it back on a few times first, to make it less tight. Applying too much pressure into the train bridge during wheel assembly can cause broken pivots…

When I find the bridge tight, I like to put the bridge on without the wheels and work it up and down to loosen it up a bit.

My mentor disapproves of this practice. He says it compromises the precision.

Whatever. 

[ifibrin]

45 minutes ago, HectorLooi said:

When I find the bridge tight, I like to put the bridge on without the wheels and work it up and down to loosen it up a bit.

My mentor disapproves of this practice. He says it compromises the precision.

Whatever. 

Hmmm…. I wouldn’t work it up and down, but put it on and take it off a few times. I guess it works out to be the same?

[JohnR725]

3 hours ago, ifibrin said:

I have worked on some ladies movements where it’s quite difficult to slide the barrel in once the train bridge is on… but those tend to be tiny movements?

It all depends upon the particular watch. Not necessarily will all watches go together the exact same way as some other watch. American pocket watches usually have the ability to remove the mainspring barrel with keeping most the rest the gear train in place. But there are some watches certain things have to go together or that not only go in at all and the entire watch left come back apart so just depends on the particular watch.

 

[Neverenoughwatches]

4 hours ago, ifibrin said:

Some train wheels bridges fit more tightly into the main plate, especially if the movement has never been taken apart before. Before placing any of the wheels into the main plate it’s a good idea to get a feel for how tightly the train bridge fits onto the main plate, so that you know how much pressure you have to apply to get the train bridge to seat properly on the main plate. If you find that you need to apply a fair bit of pressure to get the train bridge to seat onto the main plate it’s probably best to take it off and put it back on a few times first, to make it less tight. Applying too much pressure into the train bridge during wheel assembly can cause broken pivots…

Hi ifibrin, I hope you are well. Just reading through that. I very often have this problem with the balance cock. Its nearly always a tight fit and can be difficult to judge the amount  of pressure to get it into place, risking balance pivot damage. You do have to constantly check free running of the balance with each slight nudge of the cock into place. I did have one that was extremely tight that had 3 locating studs, I ended up broaching out the holes very gently which did work. I don't know how much of a good idea this is, the balance pivot alignment could be slightly off also the impulse fork entry could be affected. What do you think?

[ifibrin]

1 minute ago, Neverenoughwatches said:

Hi ifibrin, I hope you are well. Just reading through that. I very often have this problem with the balance cock. Its nearly always a tight fit and can be difficult to judge the amount  of pressure to get it into place, risking balance pivot damage. You do have to constantly check free running of the balance with each slight nudge of the cock into place. I did have one that was extremely tight that had 3 locating studs, I ended up broaching out the holes very gently which did work. I don't know how much of a good idea this is, the balance pivot alignment could be slightly off also the impulse fork entry could be affected. What do you think?

I wouldn’t broach the guide pin holes of the balance cock, since you might end up causing the entire balance cock to have side shake. If you are worried about not locating the balance pivots correctly, I suggest removing the end jewels of the balance cock (leaving the end jewels in the main-plate) before placing the complete balance. That way you can see if the top pivot has been located into the upper shock block correctly. This won’t work for fixed end jewels though.

If you are still concerned about the balance cock being too tight, then you have to remove the balance wheel and hairspring from the balance cock, and just keep putting on and taking off the balance cock.

[Neverenoughwatches]

3 minutes ago, ifibrin said:

I wouldn’t broach the guide pin holes of the balance cock, since you might end up causing the entire balance cock to have side shake. If you are worried about not locating the balance pivots correctly, I suggest removing the end jewels of the balance cock (leaving the end jewels in the main-plate) before placing the complete balance. That way you can see if the top pivot has been located into the upper shock block correctly. This won’t work for fixed end jewels though.

If you are still concerned about the balance cock being too tight, then you have to remove the balance wheel and hairspring from the balance cock, and just keep putting on and taking off the balance cock.

Thanks ifibrin, I did think the broaching  was overkill and a big risk. It was on an Obosa and a cheap watch at that , it has a lot of issues with it and tbh I think it just needs to be broken down for spares. I seem to get a lot that are tight. I work on Oris mostly, it may be something more specific to that make.

Edited April 21, 2022 by Neverenoughwatches

[ed1210]

Success!!

[Neverenoughwatches]

24 minutes ago, ed1210 said:

Success!!

Well done Ed. Perseverance.  It's just practice.  My first probably took 20 mins or so. Each time got less and less. Are you taking it off again fir another go ?

[TKM3RD]

I, too, am glad to hear there's no "magic trick" and it's just lots of practice. My bug-a-boo is the escape wheel! I let my frustration get the better of me the other day, and broke the pivot right off - probably about 3/4 intentionally. I work on discarded movements, so no big deal, but it is NOT a technique I would recommend!

Happy watchmaking!

[Neverenoughwatches]

7 hours ago, TKM3RD said:

I, too, am glad to hear there's no "magic trick" and it's just lots of practice. My bug-a-boo is the escape wheel! I let my frustration get the better of me the other day, and broke the pivot right off - probably about 3/4 intentionally. I work on discarded movements, so no big deal, but it is NOT a technique I would recommend!

Happy watchmaking!

When you start to feel frustration coming on , just walk away, go have a cuppa, then come back when you are more relaxed.

[RichardHarris123]

I asked the same question when I was new, couldn't get the plates to fit.  Sometimes it's easy now, sometimes I have to manipulate the wheels with tweezers, I'm still a relative beginner. Good advice to take your time or walk away?, I've broken too many in frustration. 

Edited February 27, 2023 by RichardHarris123

[JohnR725]

what I find helps is if things aren't going together take the plate off position the wheels again and start over. Because a lot of times when you start over somehow magically the wheels will align themselves sometimes they will not. All of us can struggle with putting the wheels into the plate. Some watches tend to be worse than others much much worse.

Then the one that's always troubling is if you're working on something modern by a modern quartz watch that has wheels are kind of hidden it wondering how the heck did the factory do it? I've seen the video the wheels come down and of course they stand up in the plate comes down straight on top and of course they go into the plate every single time of a machine could do it obviously well no I can't.

[RichardHarris123]

8 minutes ago, JohnR725 said:

what I find helps is if things aren't going together take the plate off position the wheels again and start over. Because a lot of times when you start over somehow magically the wheels will align themselves sometimes they will not. All of us can struggle with putting the wheels into the plate. Some watches tend to be worse than others much much worse.

Then the one that's always troubling is if you're working on something modern by a modern quartz watch that has wheels are kind of hidden it wondering how the heck did the factory do it? I've seen the video the wheels come down and of course they stand up in the plate comes down straight on top and of course they go into the plate every single time of a machine could do it obviously well no I can't.

Full plate, what a nightmare.  Managed to reassemble a couple but wouldn't be my first choice.