Figuring out which balance staff

Streetsnake

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Hi all,
So I'm struggling with how to figure out what balance staff I need to order for my PW. I have an Elgin 18s, grade 10, model3, class, full plate 11J. I have the American Watch Movements book. It says either an 857 or a 2516. Is that right and if it is how do I know which one. Then I go to Ofrei and balance staff.com to look and they have 7+ options available. I've tried to figure this out on my own but can't. Also, I don't want to measure the staff I have because I'm not sure it is the correct one...the balance is rubbing on the top plate. The staff doesn't look bad but I thought maybe it is incorrect and that is what is causing the issue. Thanks for any guidance.
 

MrRoundel

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You might try switching the balance jewel sides before you resort to restaffing. It seems to me that I've had balance wheels rub on the top plate due to somebody switching the jewels.

The part number looks like it would be an 857 to me. That's what it shows in the burgundy Elgin parts book for Grade 10's.
 

Dave Coatsworth

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It would indeed be the 857, but note there are 4 different versions of the 857. The Elgin book is no help in determining which one you need. There is 'new style' vs. 'old style'. Each of those comes in a 'long hub' or 'short hub' version. I believe the old style staffs are 5.97mm long and the new style are 6.1mm long. For the hubs, the short hub is 1.28mm and the long hub is 1.51mm. So, you will have to do some measuring to determine which 857 you need.
 
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Rick Hufnagel

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will be part #857 but you have different types.

New and old style, both have short or long hubs.

Screenshot_20210410-174005.png Screenshot_20210410-174037.png

Dave beat me to it, thanks for the additional measurements!

Also the upper and lower hole jewels are the same in Elgin 18s, so switching them shouldn't be an issue, unless someone corrected a previous problem by trimming one.
 

Dave Coatsworth

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There is an interesting piece of information in Rick's post that I had not seen before. That is the approximate cutoff of 3,000,000 for switching from 'old style' to 'new style'. Another useful bit of info in determining which you need.
 

Streetsnake

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so I'm in the mid/high 2M range, so I guess the old style. No to just figure out which hub it is. Ugh. If I were to replace the jewels, are those straightforward and easy enough to find? Thanks
 

Rick Hufnagel

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Knowing Elgin, I would take that 3,000,000 as a VERY general idea.

This book is From 1915. Approx 25 years after #3,000,000.

The 18s Elgin balance hole jewels are definitely not hard to find, but there are numerous pivot sizes (the hole in the jewel), which would have to be measured and ordered to fit the balance staff pivots.
 

Streetsnake

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Thanks everyone for the thoughts. So for replacing the jewels, my lower pivot measures .14 and I assume the upper pivot is the same. That would mean I needed a .15 jewel for both jewels, correct? However, since my balance is sitting tight against the plate and .15 is the biggest (that I could find) jewel, wouldn't that mean my balance would still sit in the same place? Or is there a possibility that another type of jewel was used?? Sorry, just trying to do a little reasoning before I spend $25 for some new jewls. Also, for not having worked on one of this particular model before, I noticed the lower jewel setting was not flush with the plate, it was slightly recessed. Is this atypical? I checked the setting but it was full seated and screwed down tight. Thanks all for the continued help.
 

MrRoundel

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Streetsnake , as someone mentioned above, switching the jewels (Upper/lower-Lower/upper) wouldn't help with Elgins. I've had it happen on Walthams but figured it might be common to full-plate movements. Granted, there's no particular logic in my figuring, just a WAG at something worth a shot.

And replacing should only be necessary if they're cracked/broken.

Sorry, had this one composed last night but didn't save it.
 
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MrRoundel

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It might be best if I just shut up, as it seems that I am creating confusion. But to clarify, it wouldn't be the jewel's hole size that changes the end-play. It is the thickness of the jewels and their settings that put might set things off. However, as was mentioned, this would be unlikely with Elgins. Good luck with your Elgin, OP.
 

Streetsnake

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OK. Sorry I misunderstood. I missed the comment on the jewels not helping. They don't look to be cracked. I think I know the proper staff. I'll cross my fingers and go for it. LOL
 
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MrRoundel

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Don't forget using extra care with the pallet fork/lever, as they do get slightly stuck after many years. And if the pivot is stuck, and you pull the top plate without freeing it, you stand a good chance of breaking the pivot and/or jewel. I think they get cocked a bit between at the potance (lower balance bridge/cock) and don't lift out straight. Just pay special attention and you should be fine. Maybe you know all of this already. I'm just making sure, just in case you don't. Full-plates are generally trickier to disassemble/assemble than 3/4 and bridge models.

Best of luck.
 
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gmorse

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Hi Streetsnake,
Don't forget using extra care with the pallet fork/lever, as they do get slightly stuck after many years.
Good advice, to which I'd add, dismantle and assemble full-plate movements with the dial side uppermost.

Regards,

Graham
 
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Streetsnake

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I’m trying get back to a few watches giving me issues. Please take a look at the below pics. Is the staff alright? I thought the pivots looked alright but I just don’t understand the issue if it’s not the staff.
08C2C937-CDEA-495D-A048-FF56CABCB4EF.jpeg DB5FFD98-FF50-4A85-9456-0792A716FA03.jpeg
 

Skutt50

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The first picture shows a balance pivot that is full of old debree and that needs to be cleaned and possibly polished. The corresponding jewels needs a good cleaning and oiling.

The second picture i harder to tell. Firstly it needs a good clean and probably a good polish. If it thereafter shows wear it may require a replacement but one can't tell at this point.

Another thing to check is the impulse jewel. It looks like it has come loose. Perhaps this can be fixed by heating it so the shellac melts and re-attaches .
 
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Streetsnake

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Hi All. Wanted to provide a frustrating update. So, I replaced the staff. I believe I got the correct one. Installed it, still same issue with it being sluggish and not wanting to start up/keep going after help. So, I thought I would replace the jewels since the pivots were different sizes versus the old staff. (Thought of that after the fact. Ordered new jewels, cleaned cap jewels and reassembled. Still nothing. I will stay this time the balance looks like it is free and clear of the top plate. So what now?? Mainspring? Anyone willing to let me send this thing to them so they can tell me what is wrong with it?? LOL
 

Skutt50

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Did you check the impulse jewel? It looks like it is loose in one of your pictures .....

With the balance removed, is the pallet fork snapping distinctly between its two end positions at the banking pins?
 

Streetsnake

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Did you check the impulse jewel? It looks like it is loose in one of your pictures .....

With the balance removed, is the pallet fork snapping distinctly between its two end positions at the banking pins?
Thx. I forgot to mention. I have never fixed an impulse jewel but I did heat it up. It seemed like it is secure now. As for the pallet fork, it moves between banking pins well. It doesn’t “snap” as much as I’ve felt with others but it is distinct. Hopefully that helps.
 

Skutt50

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I assume you checked the balance when you changed the arbor. With the pallet fork removed the balance should swing some 40 seconds or more if you give it a good puff with a blower or push it with a small paint brush.

If the pallet fork snaps between the banking pins and the balance swings freeely the problem should be in the interaction between pallet fork and roller table.

Could e.g. the guard pin be touching the roller table? Could the pallet fork be bent so it interacts too low or high with the roller table? Could there be some shellac spillage touching the pallet fork?
 

Streetsnake

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I assume you checked the balance when you changed the arbor. With the pallet fork removed the balance should swing some 40 seconds or more if you give it a good puff with a blower or push it with a small paint brush.

If the pallet fork snaps between the banking pins and the balance swings freeely the problem should be in the interaction between pallet fork and roller table.

Could e.g. the guard pin be touching the roller table? Could the pallet fork be bent so it interacts too low or high with the roller table? Could there be some shellac spillage touching the pallet fork?
I’ll check the balance. What would cause the balance not to swing correctly, knowing that it has a new jewel and staff. The hair spring is clean. So I would lay the balance cock on it top with the pivot in its jewel and give it a puff of air?
 

Skutt50

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So I would lay the balance cock on it top with the pivot in its jewel and give it a puff of air?
Not sure what you mean.

What I mean is to install the balance in the movement but without the pallet fork. That way you can check that the balance is moving freely. There can be several issues that prevents the free movement of the balance. One you did not mention is if the jewels are too close i.e. are "squeezing" the balance....
 

Streetsnake

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Not sure what you mean.

What I mean is to install the balance in the movement but without the pallet fork. That way you can check that the balance is moving freely. There can be several issues that prevents the free movement of the balance. One you did not mention is if the jewels are too close i.e. are "squeezing" the balance....
Alrighty. I removed the pallet fork and reassembled. It moves freely and oscillates well. I’m reassembling now. Does this look correct?
130D7824-E9B7-4B19-B3A4-C692A8AD0398.jpeg
 

Streetsnake

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Looks correct to me!
I think I might see an issue. I'll have to check it once I get back from the office. It looks like the pin that comes off the pallet fork (please tell me the correct term) is touching the top plate (dial side I think). I don't have it in front of me. If it is touching, do I just snip a tiny bit off? When I looked at it prior to installing, it didn't look bent.
 

gmorse

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Hi Streetsnake,
It looks like the pin that comes off the pallet fork (please tell me the correct term) is touching the top plate (dial side I think). I don't have it in front of me. If it is touching, do I just snip a tiny bit off? When I looked at it prior to installing, it didn't look bent.
Please don't start cutting anything until you understand why it might be touching! Are you trying it as your picture shows, with the wheels just in the top plate, or with the pillar plate in place? Without the pillar plate fitted the arbors can tilt and give a false impression.

That pin is the 'safety' pin and if it had clearance before you dismantled it, it still should.

To check the balance as Skutt has suggested you only need to install it by itself in the top plate, with the balance cock; nothing else is needed for this test. You can then give it a light puff with the blower and see how long it takes to stop oscillating, and when it does stop it should do so gradually, not stop suddenly.

Regards,

Graham
 

Skutt50

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That sounds like the safety pin. It is there to prevent overbanking i.e. to prevent the lever to move when the balance is not in the right position.

If it touches the plate it will definately cause disturbances to the movement. Before you shorten it, test the pallet fork in the movement so you are sure it is causing a disturance. If so try to understand why? Is the guard pin loose and has moved up from the fork? Is the fork bent?

Another thought is that the banking pin might only move in the opening for the balance. Are the banking pins separated to the point where the fork moves too far and thats why it touches the plate?

PS. In your picture it looks like you have double jewels in the pallet fork. Is that a mirror effect? DS.
 

Streetsnake

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That sounds like the safety pin. It is there to prevent overbanking i.e. to prevent the lever to move when the balance is not in the right position.

If it touches the plate it will definately cause disturbances to the movement. Before you shorten it, test the pallet fork in the movement so you are sure it is causing a disturance. If so try to understand why? Is the guard pin loose and has moved up from the fork? Is the fork bent?

Another thought is that the banking pin might only move in the opening for the balance. Are the banking pins separated to the point where the fork moves too far and thats why it touches the plate?

PS. In your picture it looks like you have double jewels in the pallet fork. Is that a mirror effect? DS.
To try and answer a couple questions...It looks like the safety pin is touching with the top and bottom plate screwed together. I will disassemble again and look more closely at the pallet fork to see if it has an issue. The pallet fork does have two jewels. I'll try to understand the safety pin and how it works with the plate. I guess if nothing else, this PW is helping me understand different things to look for and understand. :)
 

svenedin

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I don't know whether this is just a photographic artefact or the lighting but possibly there seems to be something wrong with the teeth of the second wheel nearest the camera.
 

Streetsnake

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FINALLY!! I'm embarrassed to say but I finally figured out the problem. The banking pins were not set correctly causing the pallet fork to rub against the escape wheel arbor. At least that is what I believe. Once I reassembled and adjusted the pins a bit, it started running. Seems to be keeping accurate time. Thanks for everyone's help on this. It was a very good learning experience of helping to figure out the issue. I just wish I would have done that prior to a new staff and jewels. LOL
 

gmorse

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Hi Streetsnake,
The banking pins were not set correctly causing the pallet fork to rub against the escape wheel arbor.
I'm glad you've found the problem, but I think your use of the terms is somewhat confused; the fork is at the balance end of the lever, and nowhere near the escape arbor. Do you mean the counterpoise tail at the escape wheel end?

Regards,

Graham
 

Streetsnake

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Hi Streetsnake,


I'm glad you've found the problem, but I think your use of the terms is somewhat confused; the fork is at the balance end of the lever, and nowhere near the escape arbor. Do you mean the counterpoise tail at the escape wheel end?

Regards,

Graham
Sorry about that. I was using the term in an overarching way. Yes, the counterpoise tail. Thx. Ben
 

karlmansson

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Hi Streetsnake,


I'm glad you've found the problem, but I think your use of the terms is somewhat confused; the fork is at the balance end of the lever, and nowhere near the escape arbor. Do you mean the counterpoise tail at the escape wheel end?

Regards,

Graham
It looks like the bankings are on the side of the counterpoise on this watch. The more common arrangement would be to have the bankings closer to the impulse jewel on the fork side.

Ben, a common mistake when there are issues with the escapement is to move the banking pins before assuring that the locks on the pallet jewels are set correctly. Moving the bankings will affect the locks but will also alter the impulse angle. To boil it down: moving the jewels is a linear adjustment and moving the bankings is an angular adjustment (that also affects the linear adjustment of the pallet jewels). It's complicated and everything interconnects.

I usually start out by looking at the bankings to see if anything looks bent or adjusted out of what I can expect to be factory spec. I mostly work on European wristwatches that do not have moveable bankings so for a watch with screw-in bankings it will be harder to notice.

To explain the above: A general rule is that the lock should be around 1/3 (some say 1/5) of the impulse surface of the pallet stone. A microscope helps with this inspection. While you can change the way the escape wheel teeth interact by moving the bankings (moving them apart will cause them to hit the pallet earlier in it's rotation and the mesh between pallet rotation and EW rotation will be shallower at that point) this will also alter the time that the balance impulse jewel interacts with the pallet fork. You have increased the lift angle. This will first and foremost change how detached the balance is from the escapement, a larger angular percentage of the full turn of the balance is spent in contact with the fork. This will affect timekeeping to the worse and also brake the balance for a longer time while giving a less sharp impulse. The impulse jewel will hit the fork horns at a steeper angle and may even hit an edge. You also disturb the timing between contact of the impulse jewel and fork and impulse on the pallet stone. Unlocking will occur before the the balance has passed "0" on its beat and will recieve impulse while still being accellerated by the hairspring.

It's really hard to try and invent the wheel again in these circumstances as it's all interconnected. That's why I always attempt to restore to visual original before attempting to adjust based on timing machine results. If something is rubbing though, that sounds like it may be one of those instances where you need to restore to as close to factory as possible, and also might be the source of your problem. But have a look at the pallet stones too to make sure that the lock looks acceptable and is even between the two sides.

Best of luck!
Karl
 

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