Hampden pocket watch 2575591 16s Balance not moving freely (replaced balance staff)

[BillM]

I recently replaced a broken balance staff on a Hampden 16s pocket watch (first time doing this). This included truing and poising the balance.
After reassembling the watch (after a complete cleaning) the watch does not want to stay running.
I removed balance and pallett, then reinstalled the balance.
The balance rotates freely in all positions except in the dial down position. It looks like it's dragging slightly and then comes to a sudden stop instead of smoothly occeilating.
I have inspected the jewel and it looks ok to me.
The end shake also seems right, but I am a beginner with this kind of work.
Any suggestions on what I got wrong here or am missing?
Thanks,
Bill
 

[JohnR725]

When you purchased your replacement staff did you measure it and compare it with the staff that you  removed from the watch?

5 hours ago, BillM said:

The balance rotates freely in all positions except in the dial down position. It looks like it's dragging slightly and then comes to a sudden stop instead of smoothly occeilating.

Possibly isn't the jewel.

It would be nice if you remove the balance with Ridge flip it over and give us a picture as I don't like the image I'm seeing here. This is a bimetallic balance wheel if I look at the top of the image the gap is nice and small but on the bottom of the image they gap appears to be hopefully optical illusion it looks to be quite huge?

 

 

 

[BillM]

You’re right, in the photo I provided the balance was in very bad shape. I used that photo as a reference to show what I was working on, sorry.
here is a photo of the balance after being trued and poised and reassembled.  
 

[JohnR725]

It's hard to tell in the second photo but looks like the arms might be bent in just a hair? Not the reason why it's stopping low

Then did you verify that the new staff looks exactly like the old staff preferably measuring with a micrometer. Often times there can be staff size variations even for the same part number

8 hours ago, BillM said:

. It looks like it's dragging slightly and then comes to a sudden stop instead of smoothly occeilating.

Sudden stops are very bad. If you listen to the watch or this case the balance wheel when it makes a sudden stop can you hear anything? Also pay attention to the hairspring over coil hairsprings have to be while the little more tricky than flat hairsprings you want to make sure it's not touching the balance arms the over coil isn't touching of the upper bridge. I doubt a bad jewel would cause a stopping issue like you describe more like it's rubbing on something else perhaps

 

[BillM]

I measured the old and new staff and found a .0005”difference maximum, that was at the diameter of the step that the roller table is pressed onto, and figured that was close enough. 
I’ll look at the hair spring more closely. 

Edit: Well apparently I did not get a good measurement on the old broken staff pivots.  After looking real close again, I have found that the pivots do not protrude through the jewels at all. 
So there’s the issue. 

I do have a bottle of jewels and cap stones and I have an extra staff, so the question is:

Do I try to turn down the pivots on my spare staff to fit the jewelers currently installed or,

do I try to find jewels that fit the currently installed staff and replace them in the cock and main plate?  

Edited September 14, 2023 by BillM

[BillM]

Feel pretty dumb for not checking the staff pivots fit to the jewels before setting the staff to the balance, Live and learn eh?

Edited September 15, 2023 by BillM

[JohnR725]

 

American pocket watch staffs are interesting. For instance Elgin and 18 size staff part number 857 comes in four different variations basically new style old-style and in each of those has a variation. Plus each of those has more than one pivots size 2 of them have only to pivots size the other two have five different pivots sizes. All for one part number

now for your watch there's only 2 16 size staffs and conveniently no pivots sizes indicated. Usually it's preferred to have an oversized have it as you can reduce it to fit

depending upon the tools you have you can reduce the pivot to the correct size. It's preferred if you can do it without being on the balance staff as if you make a mistake have a problem or whatever and then you don't have to re-staff again but you can do it on the balance wheel is still depends upon what tools you have available

https://pocketwatchdatabase.com/search/result/hampden/2575591

Then randomly focusing to find the correct balance jewels I wish you well on that endeavor here's a clue of yes there were different pivots sizes this is a listing of the balance jewels

 

 

[Nucejoe]

Sudden stop indicates something hitting or severly rubbing on the balance rim/screws .

 The jewel and pivot on cock side look off center,  is it ?     this  lets balance to tilt thus its rim rubs on mainplate. 

 Moving the lower and perhaps upper balance jewel would fix that, but are this type of settings movable ? 

 

 

 

 

[BillM]

11 hours ago, Nucejoe said:

Sudden stop indicates something hitting or severly rubbing on the balance rim/screws .

 The jewel and pivot on cock side look off center,  is it ?     this  lets balance to tilt thus its rim rubs on mainplate. 

 Moving the lower and perhaps upper balance jewel would fix that, but are this type of settings movable ? 

 

 

 

 

After looking real close again, I have found that the pivots do not protrude through the jewels at all. 
So there’s the issue. 

[JohnR725]

1 hour ago, BillM said:

After looking real close again, I have found that the pivots do not protrude through the jewels at all. 
So there’s the issue. 

I found some helpful images for you in this first one they talk about freedom or side shake and there's a reference the pivot versus the jewel size. If you're lucky wouldn't have to replace the jewels because ideally in vintage it's best not to replace things unless you really have to as it tends to introduce new problems.

So if you're not replacing the jewel the numbers become meaningless because you probably won't know the size the jewel anyway and then there's a minor problem with that because in vintage the jewels aren't necessarily both the same size. There may have been variations depending upon when the watch was made at least a tiny amount and if you get people changing the jewels then you can end up with different size holes which definitely becomes an issue.

 

So at the very bottom of this image you can see where it has the reference to you can use the whole jewels as a size gauge for your pivot. In other words the pivot has to go through the hole.

How the second image below shows greatly magnified pivots and you can see not a lot of clearance. The pivot definitely has to go through the hole and if the end stone was not in place you can see where it would protrude through. How if your pivots do not fit the hole at all then you would have a very serious problem especially if you tighten down the balance bridge as you probably either break a jewel or break some pivots.

 

[Nucejoe]

5 hours ago, BillM said:

After looking real close again, I have found that the pivots do not protrude through the jewels at all. 
So there’s the issue. 

 So the pivot can jumps out of jewel hole, then balance tilts, thus the sudden stop.

 

[BillM]

3 hours ago, Nucejoe said:

 So the pivot can jumps out of jewel hole, then balance tilts, thus the sudden stop.

 

Well said!  

7 hours ago, JohnR725 said:

I found some helpful images for you in this first one they talk about freedom or side shake and there's a reference the pivot versus the jewel size. If you're lucky wouldn't have to replace the jewels because ideally in vintage it's best not to replace things unless you really have to as it tends to introduce new problems.

So if you're not replacing the jewel the numbers become meaningless because you probably won't know the size the jewel anyway and then there's a minor problem with that because in vintage the jewels aren't necessarily both the same size. There may have been variations depending upon when the watch was made at least a tiny amount and if you get people changing the jewels then you can end up with different size holes which definitely becomes an issue.

 

So at the very bottom of this image you can see where it has the reference to you can use the whole jewels as a size gauge for your pivot. In other words the pivot has to go through the hole.

How the second image below shows greatly magnified pivots and you can see not a lot of clearance. The pivot definitely has to go through the hole and if the end stone was not in place you can see where it would protrude through. How if your pivots do not fit the hole at all then you would have a very serious problem especially if you tighten down the balance bridge as you probably either break a jewel or break some pivots.

 

Thank you for this information, much appreciated!  

[Nucejoe]

10 hours ago, BillM said:

I have found that the pivots do not protrude through the jewels at all. 

I hold the movement above my head ( in face down position )  to see if the pivot  ( on mainplate side )  does protrude through the jewel.

The likely senario is that it ( the pivot ) does so much excessively protrude through the jewel ( on mainpalte ), that pivot shoulder  sits on the jewel, as a result there be unwanted friction thus poor amplitude and eventually sudden stop as expalined above.

Does the setting on mainplate have capstone ?   

Do you feel any side shake ( mainplate side )   ?

 

 

 

[BillM]

17 hours ago, Nucejoe said:

I hold the movement above my head ( in face down position )  to see if the pivot  ( on mainplate side )  does protrude through the jewel.

The likely senario is that it ( the pivot ) does so much excessively protrude through the jewel ( on mainpalte ), that pivot shoulder  sits on the jewel, as a result there be unwanted friction thus poor amplitude and eventually sudden stop as expalined above.

Does the setting on mainplate have capstone ?   

Do you feel any side shake ( mainplate side )   ?

 

 

 

Yes, there is a capstone on the main plate setting. 
No side shake at all, or end shake.  
Using my stereo microscope, I can see that the pivots are not protruding through the jewels. 
I have a spare balance staff and the pivots are the exact same size as the one I installed on the balance. I used this staff to check fit and they do not go through the jewels.  
So, it looks like I will have to turn down the pivots to fit, the problem is, I can’t get my lathe to run truer than  .0005” I’m also afraid of breaking the pivots.  

[JohnR725]

47 minutes ago, BillM said:

turn down

Turn isn't exactly the right term. In other words you're not going to use a graver and reduce the size. I have a link below scroll down to the section titled Joseph School of Watch Making. You can either do the sections or the bottom of the list the entire book would be preferred. Then there is a section on making a balance staff but you really need the next number four as act covers reducing the pivots size to what you need.

Then I'm still truly amazed that you were able to tighten the balance bridge down when the pivots are not in the holes because it would make me wonder if your balance staff is too short

when you ordered your balance staff Did it have a part number?

https://www.mybulova.com/vintage-bulova-catalogs

 

 

[BillM]

1 hour ago, JohnR725 said:

Turn isn't exactly the right term. In other words you're not going to use a graver and reduce the size. I have a link below scroll down to the section titled Joseph School of Watch Making. You can either do the sections or the bottom of the list the entire book would be preferred. Then there is a section on making a balance staff but you really need the next number four as act covers reducing the pivots size to what you need.

Then I'm still truly amazed that you were able to tighten the balance bridge down when the pivots are not in the holes because it would make me wonder if your balance staff is too short

when you ordered your balance staff Did it have a part number?

https://www.mybulova.com/vintage-bulova-catalogs

 

 

The part number is 3720. 
I will read the information you linked, thank you. 

Wow!  Thank you JohnR !  Wonderful information and many many hours of reading and learning!  Just fantastic, thank you for that link!
 

 

[BillM]

After re-reading your post again JohnR, I looked at the available balance staffs and found an older style, Part# 2720 that is 5.6mm long, the part # 3720 is 5.13mm long. So it all kind of adds up, the staff I have is too short.

There's no pivot size number, but I'm betting they are smaller, so I ordered two and well see,

Edited September 17, 2023 by BillM

[JohnR725]

I was doing a search in another discussion group to see if I can get any staff information I found this

The 2720 (old number 159) is 5.60 mm long. The balance seat is 1.27, hairspring seat 0.76 and the roller seat is 0.68-0.71 in diameter near the hub. The hub is 0.65 mm long

The 3720 (old number 627) came in two styles. Style 1 is 5.13-5.15 mm long. The balance seat is 1.27, hairspring seat 0.75 and the roller seat is 0.71 in diameter. The hub is 0.52 mm long

The 3720 style 2 is 5.51 mm long. The hub is 0.55 mm long. The other measurements are the same.

There was yet another 16 size staff, the old number 158. It is 5.75 mm long. The balance seat is 1.30, hairspring seat 0.82 and roller seat 0.72 mm. The hub is 0.75 mm long.

This by the way is the classic problem of American pocket watches variations in parts. Plus variation with the same part numbers.

Oh and once I realize there was a material book found one of the pocket watch database. The problem with a lot of reference books like we can see here is they're basically worthless for details. Some companies did a much much better job like Elgin describes all of their variations here not very helpful at all

[BillM]

Thanks JohnR,

its sounding like I’m going have a collection of Hampden balance staffs before I get the right one. 

[nickelsilver]

This is why 99% of the time i make the balance staff. From a professional perspective, not counting American stuff, for average  AS stuff for example, there might be between 2 and 6 possible staffs. By the time you determine the exact one you need, then find a supplier who has it,buy it and ship it, to find out they sent the wrong one or the righr one but it's rusted etc. dang I make it for less effort.  But I've made them regularly for a quarter century; seems to be a rare thing.

 

As John has mentioned there are often different pivot sizes, which means different jewel sizes. Jewels and staffs were easy to get even for less common American stuff 30 years ago. Not uncommon to see staffs altered because someone had a 0.09 jewel on hand but the staff they replaced with had 0.10 pivots. These things often were serviced yearly or close to it. Bottom line was get it ticking and get it out.

 

You could easily have wrong sized or different sized jewels, as a start.

[RichardHarris123]

10 minutes ago, nickelsilver said:

This is why 99% of the time i make the balance staff. From a professional perspective, not counting American stuff, for average  AS stuff for example, there might be between 2 and 6 possible staffs. By the time you determine the exact one you need, then find a supplier who has it,buy it and ship it, to find out they sent the wrong one or the righr one but it's rusted etc. dang I make it for less effort.  But I've made them regularly for a quarter century; seems to be a rare thing.

 

As John has mentioned there are often different pivot sizes, which means different jewel sizes. Jewels and staffs were easy to get even for less common American stuff 30 years ago. Not uncommon to see staffs altered because someone had a 0.09 jewel on hand but the staff they replaced with had 0.10 pivots. These things often were serviced yearly or close to it. Bottom line was get it ticking and get it out.

 

You could easily have wrong sized or different sized jewels, as a start.

Interesting point, the jewel has been changed so even the correct staff may not fit, isn't watch repair fun? On average, how long does it take you to make a staff? 

[Nucejoe]

I wish I had your patiance Bill.

jd would have repivotted the broken staff, for the fun of it I suppose. 

https://www.watchrepairtalk.com/topic/22028-repivoting-a-balance-staff/

Good luck pal.

 

 

[BillM]

Well,  patience or no patience, I’ve learned SO MUCH working  on this watch. I really hope to get it going correctly, but if not I’ll move on to the next one and do my best to apply what I’ve learned with this one, and get the next one done right. 
I’ll keep ya all posted as to the final results, it’ll be another week as I’m waiting for the new staff to be delivered.  
thanks for all  the help guys!  
 

[BillM]

 I received my new balance staff and found that the pivots fits the balance cock jewel but not the main plate jewel. The main plate jewel is smaller. 
Very frustrating say the least.

So I can try to reduce the size of the lower pivot or try to replace the jewel in the main plate.  
im probably going to try to reduce the size of the pivot.  
 

[JohnR725]

1 hour ago, BillM said:

Very frustrating say the least.

this is the unfortunate problem of vintage watches where somebody before you made a repair for them with zero thought of what will happen in the future. In other words it was convenient for them to change the jewel and not worry about you at all.