Shortening the Pallet Fork Jewels

Discussion in 'Watch Repair' started by Ben S., Feb 21, 2020.

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  1. Ben S.

    Ben S. Registered User

    Dec 7, 2019
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    Hello all,

    Ok, new development in the case of the Waltham 3/0 I’ve been working on for the past week. (Here are the first two threads on the subject: Cleaning Off Gunk From the Dial and Cleaning / Shining a Gold Case )

    After cleaning off the heavy gunk, I thought the gear train should turn... it should, but it doesn’t. A look though the triple lens magnifier at the pallet fork revealed the problem.

    According to the Watch Repairer’s Manual by H.B. Fried, the pallet jewels should only contact the tips of the escapement wheel teeth by about 1/3 of the jewel’s thickness. In this watch, the pallet jewels contact the escapement wheel teeth by about 90% of the jewel’s length! Not wonder it’s not working!

    (I’m thinking the pallet jewels were replaced but not shortened to their proper length. Then the watch was sold when it wouldn’t work, and the next owner squirted WD-40 through the crown in a effort to get it working. When that didn’t help, it came up for auction on eBay, which is where I come in....)

    My question is this: is there any way to shorten the pallet jewels without having to remove them from the pallet fork and then shellac them back in place? And, what’s the best way to shorten the jewels?(Diamond belt sander? Etc.)

    Thank you in advance,

    Ben. S.


    P.S. I can’t attach pictures because they won’t turn out. I can’t even see it well until that third lens... I don’t think my phone’s camera can either....
     
  2. gmorse

    gmorse Registered User
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    Hi Ben,

    If the wrong length pallet jewels have been fitted, the only suggestion I have is to find the correct ones and fit them. If you try and shorten these you'll probably only succeed in destroying them, and if you do it while they're still mounted you could destroy the whole thing. Are you sure they haven't just been shellacked in the wrong position, ie, too deep into the escape wheel?

    Regards,

    Graham
     
  3. topspy

    topspy Registered User
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    Nov 17, 2013
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    The proper way to move the pallet stones is to use a pallet warming tool such as those shown. The little levers are used to push the stones in once you have softened the shellac over an alcohol burner. I've only had to do this a few times as it rarely comes up (usually a broken pallet jewel or one that is loose.) It's tricky as moving one stone changes the depth of engagement of the other. Also you need to check whether someone has messed with the banking pins. The quick and dirty way to check this is to put in another pallet fork from the same model watch. If it does the same thing, then the banking pins are the problem, or at least part of the problem. IMG_2422.JPG
     
  4. Ben S.

    Ben S. Registered User

    Dec 7, 2019
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    Hi Graham, Topspy,

    Thank you for the comments and advice. Yes, I’m sure the jewels are pushed in all the way. There’s not even a little space left that I could see.

    I’ll try to find a new set of jewels, but may end up having to shorten these ones.

    These banking pins appear to rotate from side to side, by means of a Philips head screw on the bottom of the banking pins. I suppose it’s possible that someone may have turned these a little, thus causing overbanking.

    I don’t have another pallet fork from this size Waltham to fit and see if it would work. The next size Waltham I have is a 12s. So... would you recommend I experiment and turn the screws to shorten the distance the pallet fork and rotate, or should I leave it alone for now?
     
  5. gmorse

    gmorse Registered User
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    Hi Ben,

    By all means try adjusting the banking, which is a reversible adjustment, whilst grinding lumps off the pallet jewels isn't! You have very little chance of returning the jewels to the correct angles or level of flat polish if you start down that track. Those adjustable banking pins are an open invitation to tinker!

    Regards,

    Graham
     
  6. topspy

    topspy Registered User
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    Those banking pins don't use a philips screwdriver. They just have two slots at right angles to each other. So, you can use a regular screwdriver. It's best to make a tiny mark showing the starting position with a fine sharpie so you can return to the original position if needed.

    You can safely shorten the pallet jewels by removing them from the fork and shortening the BACK of the jewel. To do this requires shellaccing them to a small brass plate (for control) and using a lap with diamond paste on a lathe. That being said, it's not that hard to source new ones as they came in almost all of the Seitz jewel assortments.
     
  7. Ben S.

    Ben S. Registered User

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    Update: I tried to change the positions of the banking pins, using the guidelines and pictures in the Watch Repairers Manual. It definitely helped a lot, but not quite there yet. The left jewel is still too far out. However, changing the lighting revealed that there is a very small amount of space left that I could push the jewel in more. I’ll give it a try when the pallet fork heating tool comes in.... Thanks all!
     
  8. GeneJockey

    GeneJockey Registered User
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    I have read repeatedly that one shouldn't use the banking screws to adjust lock, but it was only the other day that I finally read a comment on another watchmaking forum that explained why. The commenter said the banking pins are for adjusting the interaction of the pallet and the safety roller, and the depth of lock is all adjusted by moving the jewels.

    Finally, it made sense!

    Mind you, in this case, and in the case of a number of older watches, a previous owner may have used the banking pins to adjust lock, and thus screwed up the pallet/safety roller interaction.
     
    karlmansson and gmorse like this.
  9. karlmansson

    karlmansson Registered User

    Apr 20, 2013
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    That is a good way of putting it! Another thing to remember is that by moving the bankings you are also altering the lift angle of the escapement, making amplitude readings on your timing machine inaccurate. You will need to visually confirm and amplitude of 180deg (easiest to see) and adjust the lift angle on your timing machine until that too shows 180 deg amplitude.

    Whenever I’m starting service on a watch, and I’m not perfectly certain that I’m the first one to service it, I always start out on the premise that there might be quite a number of things that I “shouldn’t” do during a service that I may have to do for the simple reason that someone else did it before me. And by that I mean undo a previous adjustment. Straightening banking pins, removing pig ears under the balance, re-establishing centers of bushings that have been peened etc. Sometimes you have to address methods that are bad practice and understand the mechanics of them, only to be able to undo the results of them.

    Regards
    Karl
     
  10. karlmansson

    karlmansson Registered User

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    Although it sounds like you have found a different cause for your problem, an d a solution to it, if you really do want to shorten the stones I think the only safe option is to remove them from the pallet, shellac them to a holder and grind the back end of them. The front faces have very precise angles ground on them and the polish is incredibly important. If you grind the back end you will still have the sides as reference in the slots.

    Look up Steffen Pahlow’s YouTube videos. He does a fair amount of jewel grinding on his lathe. He uses diamond powder and pastes on a brass or wooden disc and then uses a tilting saw table attachment to rest his holders against while grinding. Using bonded diamond tooling will likely shatter your pallets. Go slow and don’t push too hard or the shellac will melt from the friction.

    Regards
    Karl
     
  11. Al J

    Al J Registered User

    Jul 21, 2009
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    I use a proper escapement meter and heater...

    T3_zpsnk24m7bm.jpg

    This helps to know how much the jewels are moved, and enables you to put them right back where you started if needed (for example if the depth is fine but the jewels need to be reset due to shellac coming off). Using a tool like this and an appropriate timing machine, you can dial in the amplitude in each direction to be the same, and move it up and down as you please.

    Not cheap tooling, but often can be found used for a more reasonable price.

    Cheers, Al
     
    4thdimension likes this.
  12. DeweyC

    DeweyC Registered User
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    Ben,

    Others have told you the correct ways to do things. The only thing Fried is good for is his chapter on verge watches. Here is a link to a document that will give you all you need to know about adjusting locks; including the fact that there is much that needs to be done correctly before that.

    https://www.historictimekeepers.com/documents/Watch%20Adjustment.pdf

    The tools shown by topspy are essentially useless. They do not provide for repeatability or fine enough adjustments. The tool shown by ALJ is what most watchmakers use and I in fact still have mine. But I use the reticle in a microscope as shown in the document above because t is simpler. But both the Bergeon tool and the reticle method are the only means that are repeatable. In other words, if 3 increments turned out to be too much, you can replace it in the setup and change the adjustment by one increment.
     

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