Adjustable Banking Pins

[RyMoeller]

This question may sound a bit foolish but I thought I'd throw it out there anyway.  I've noticed on American pocket watches the banking pins are adjustable but I'm a bit perplexed as to why this would be necessary. I'm also wondering what the effect would be should one go in and adjust those pins.

[JohnR725]

Remember at the time these watches were made even though we were in mass production interchangeable parts they weren't entirely interchangeable. So this required that the escapement was adjusted at the factory. Then conceivably it wasn't just the banking pins that were adjusted the pallet stones moved in it out.

So what is the effect of adjusting the banking pins? Absolute worst case is the watch will not run at all. Usually they been just slightly miss adjusted this causes all sorts of strange problems. For instance would you like to reduce the amplitude of the watch? Putting the banking pins in the right position will do that for you.

The problem with American pocket watches and adjustable banking pins are that their adjustable. So adjustable and a variety of watchmakers between then and now what are the chances that they've been moved?

What becomes interesting is with modern watches where the banking pins are not adjustable escapement adjusting is still being taught in schools out there. So quick search on Google here's a link talking about things in the escapement. Not as much emphasis on movable banking pins when they're not movable but they can be bent. Strangely enough the Swiss even make a tool to do that.

http://raulhorology.com/2012/10/setting-up-the-escapement-eta-6498-end-shakes-divisions/

[RyMoeller]

Ah, thank you for that response @JohnR725. I've seen many a Swiss watch with banking pins bent various directions and always discovered that straightening the pins resulted in a watch which ran better thus making adjustable pins seem like madness.  Now that I've begun working on some older American watches, I have discovered that the tolerances were not as tight back in the day and every part is identical, hence the need for matching serial numbers!

Naturally the movement I'm working on today has had the banking pins adjusted post production.  Perhaps the pallet or escape wheel were replaced as the serial number scratched on the balance matches the main plate and balance cock.  It runs well but with low amplitude and I'm running out of areas to find the missing degrees.  A quick adjustment of the banking pins confirmed they are not the culprit.

[digginstony]

I've had a Waltham where the adjustable pins were played with and it was JohnR725 that helped me make the necessary adjustments. I think a lot of these issues are caused by would be watchmaker trying to remove the pins as part of servicing.
The American makers at the time made great emphasis on parts being interchangeable but I haven't found this so, certainly within the escapement and think there was still quite a high degree of hand fitting and adjustments of parts

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[oldhippy]

I'm also wondering what the effect would be should one go in and adjust those pins.

All hell would break lose. It might not escape, it could overbank, there could be no way of regulating the power, all the power could just run down, balance wheel action would go bananas. This is just a few of the major reasons why you should not play with the banking pins unless you know what you are doing.

 

[JohnR725]

1 hour ago, oldhippy said:

All hell would break lose. It might not escape, it could overbank, there could be no way of regulating the power, all the power could just run down, balance wheel action would go bananas. This is just a few of the major reasons why you should not play with the banking pins unless you know what you are doing.

So I agree with oldhippy that playing with banking pins is definitely not something you should be doing unless you grasp what you doing.

One of my watchmaker acquaintances learned watchmaking from his grandfather who ran some sort a little school on the East Coast and he instilled in David never ever touch the banking pins. But this now presents an interesting problem in that between when the factory put them where there supposed to be and you having the watch for repair what do you do if they're not adjusted correctly? So unfortunately this means that not everyone follows the rule and you may have to at some point in time learn how to adjust the banking pins.

 

[JohnR725]

3 hours ago, RyMoeller said:

Naturally the movement I'm working on today has had the banking pins adjusted post production.  Perhaps the pallet or escape wheel were replaced as the serial number scratched on the balance matches the main plate and balance cock.  It runs well but with low amplitude and I'm running out of areas to find the missing degrees.  A quick adjustment of the banking pins confirmed they are not the culprit.

One of the problems with not asking the correct question is you do not necessarily get the answer you want. So it appears to be you actually have two separate questions second one quoted above? So I would suggest posting a new question telling us that your watch is not running adequately description of the watch perhaps a picture and you're more likely to get a answer then having the question part way through conceivably an entirely different discussion.

[rodabod]

One of the issues which you can encounter is if the banking pins have been spread apart.

From "Modern Methods On Horology":
 

Quote

 

Some think the locking may be increased by opening the banking pins. This is not so as the locking is determined by the position of the pallet stones. By opening the banking pins, the locking appears greater as the "draw" causes the "run" (the "run" is the movement of the pallets after lock).

If the watch is banked to the drop, there will be no run, but as the banking pins are opened, the lever is allowed greater angular motion, and the draw of the pallet stones holds the lever against the banking pins.

 

I think in short, excessive spread of the banking pins increases draw and will waste energy in the escapement (ie. result in lower amplitude).

Edited September 13, 2017 by rodabod

[digginstony]

Setting the pins to there furthest position can be a means of obtaining a heartbeat in a non running watch, if only a very poor beat. Then making adjustments. Much to my horror I soon discovered, making adjustments to one pin ie.. the entry stone side effects the adjustment you've made on the other side and how the exit stone behaves.
I think making adjustments really belongs in the realm of the skilled Watchmaker

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[digginstony]

Also the slightest adjustment will effect the beat error

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[RyMoeller]

On 9/12/2017 at 0:22 PM, JohnR725 said:

One of the problems with not asking the correct question is you do not necessarily get the answer you want. So it appears to be you actually have two separate questions second one quoted above? So I would suggest posting a new question telling us that your watch is not running adequately description of the watch perhaps a picture and you're more likely to get a answer then having the question part way through conceivably an entirely different discussion.

Well I don't think I asked the wrong question as I kept the topic narrow on purpose.  It is true I'm still investigating issues with the movement currently on the bench but my interest was only in knowing reason for adjustable banking pins and what impact adjusting those pins would have on a movement in good repair.  The ensuing conversation has been enlightening.