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Explaination of Glycine Airman movement

  1. pdxleaf Jul 3, 2021

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    While servicing my Glycine Airman, Jim at Nevada watch repair found a problem. His explanation to me of the problem and its cause was so thorough and educational that it seemed like something others would also enjoy. So with his permission, here is his explanation for the problem with my watch, which also explains how the watch would normally function.

    Again, thanks to Jim for both the excellent description and for being kind enough to allow me to share it.
    ‐‐----------------

    Wed 6/30/2021 3:54 PM

    Dave,
    While working on your watch I made a troubling discovery. The minute wheel post has been broken at some point in the past and improperly repaired. This is the sort of thing one only finds when doing a complete disassembly. I was aware of your observation that the watch was losing large amounts of time. Usually, this is because of a loose cannon pinion. The cannon pinion on your watch was very loose, but there was more.

    I have some photographs and will attempt to explain the situation. The first image is of the movement with the dial and calendar parts removed.
    thumbnail_coseo1.jpg
    The brass gear in the center is the hour wheel (in watches, what would normally be described as gears are called wheels. With the invention of watches dating back to the sixteenth century, there is probably some archaic reason for the term "wheels". The hour wheel is the part that carries the hour hand. On the upper left, you will see there is a very small pinion that turns the hour wheel.
    thumbnail_coseo2.jpg
    With the hour wheel removed, that pinion for turning the hour wheel is part of the minute wheel. The pinion is very small, in order to get the correct gear ratio so that the hour wheel only turns once a day, rather than twice a day as in a watch with a twelve-hour dial.

    The minute wheel is turned by the cannon pinion, which is the steel part in the center of the movement. The cannon pinion fits over the center wheel arbor and is a sufficiently tight fit that when the center wheel turns, the cannon pinion turns with it, driving the minute and the hour wheels as well as the date disc.

    In order to set the watch, one must be able to turn the cannon pinion, which is why it is driven by friction. It is tight enough to turn the hands without slipping, but not so tight that it won't slip when setting the hands. You can see the setting wheel in the upper center. With the stem in the setting position, turning the stem turns the setting wheel which turns the minute wheel and the cannon pinion.

    There is a hole in the center of the minute wheel, and the minute wheel turns on a post, the minute wheel post, which is a part of the movement plate. Because the pinion is so small, the minute wheel post needs to be very small as well and consequently not particularly robust.

    The friction of the cannon pinion is adjustable by a dent in the tubular portion of the cannon pinion. This can be a delicate adjustment--tight enough to turn the hands, not so tight as to stress the setting parts.

    Sometime in the past, either a previous repairer over tightened the cannon pinion, or the cannon pinion became seized from lack of lubrication, and in the operation of setting the hands, the minute wheel post was broken. The minute wheel post was subsequently replaced by a previous repairer, but the post is slightly off-center from its original location. The result is that the mesh between the gear teeth on the minute wheel and the gear teeth on the cannon pinion has no clearance. In the closeup image below compare the clearance with the setting wheel with the clearance to the cannon pinion. The teeth can butt and stop the watch. I am suspecting that the person who replaced the minute wheel post deliberately loosened the cannon pinion friction in an obviously unsuccessful attempt to overcome the off-center condition.
    thumbnail_coseo3.jpg
    In this image, and in the closeup below, you can see the evidence of an unskillful attempt to replace the broken minute wheel post.
    thumbnail_coseo4.jpg thumbnail_coseo5.jpg
    This watch, in its present condition, will not be reliable. I cannot service the watch and offer a one-year warranty because there is a very strong likelihood that you will be sending the watch back to me. The minute wheel post can be correctly repaired/replaced.

    However, it is costly and takes much time. I do not do this work myself. I have a colleague who is equipped with the sort of precision equipment required to precisely locate the post where it should be. The cost to do this is $475.00 and may take two months or longer. Considering the other issues with the watch, you may wish to consider the economic viability of restoring the watch to good running condition.

    It is disappointing to me to be the bearer of bad news and surely this is disappointing to you as well.
    Kind regards,
    Jim
    James Sadilek, Carson City, NVwww.nevadawatchrepair.com
    Glycine Heritage Agent for the U.S.
    Free Watch Parts Search Website
    -- www.ccwatchmaker.com
    Co-owner/Moderator of Horology Matters Groups.io
    ‐----‐---------------

    Postscript

    If you made it this far you may wonder what has happened next. Jim will get the post fixed and continue with the service. It adds time and money but hey, it's only time and money compared to saving a watch.

    Also, the shadows in the photo make the plate appear rusty and pitted, but Jim says it isn't. In case anyone wonders.

    Hope all you budding watchmakers enjoyed this as much as I did, not to mention gained an even greater appreciation for the skill and knowledge of watchmakers.

    Cheers
     
    Edited Jul 3, 2021
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  2. Walrus Jul 3, 2021

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    Damn I would be more impressed with my watchmaker if he took the time to give me info like that. Granted I haven’t had that problem but I find that really cool he provided a cool educational thing like that. Shoot last time they forget to tell me my KS was done.
     
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  3. Dan S Jul 3, 2021

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    I’ve enjoyed my interactions with Jim as well. :thumbsup:
     
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  4. blufinz52 Hears dead people, not watch rotors. Jul 3, 2021

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    Great post! :thumbsup:
     
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  5. krogerfoot Jul 3, 2021

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    I talked to Jim about servicing the Airman I picked up at the beginning of the pandemic, before EMS stopped shipping to the US and at the outset of a very long slide into near-bankruptcy. He commented on the photos I sent with similarly generous and educational attention to detail. Now that things have finally stabilized somewhat I should get around to finding a way to get it to him. I’m also considering sending one of my kids to apprentice with him and carry on his work keeping so many of these singular watches in brilliant running condition.
     
  6. pdxleaf Jul 3, 2021

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    There's probably more than a few of us who would like to "powder ourselves at the dust of his feet" so to speak. It would be a brilliant choice.
     
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  7. krogerfoot Jul 3, 2021

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    Hmm, it was already May when I had packed up the watch on the right to send it to Nevada. Time to look into that project once more.

    1AE6B287-97C5-4476-AB2C-B53346353409.jpeg
    196ABDCE-A7FB-4949-A6C9-A67807C5CBD1.jpeg
     
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  8. Archer Omega Qualified Watchmaker Jul 4, 2021

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    This is not a completely uncommon thing. I had a Speedmaster with the same issue a few years back - here is how the minute wheel fit on the "post" that some hack installed:

    [​IMG]

    And the wonderful repair that hack did:

    [​IMG]

    The part that was jammed into the hole was actually square, so who says you can't fit a square peg into a round hole?

    And what a proper repair looks like:

    [​IMG]

    Cheers, Al
     
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  9. pdxleaf Jul 4, 2021

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    Seeing your examples really emphasizes how poorly repaired mine was. Jim was kind in describing the workmanship of my previous repair.

    Jim further explained that this post is cut out of the brass plate at the factory (Is what I'm calling a post technically a pinion?). He also said the post would be made of steel and stronger than original, which is encouraging.

    What is hard to imagine is the scale. I confess to feeling sympathy for the hack. I understand welding and lathes and grinding (I worked as a welder during college in factories that made skid steer loaders and then later horse trailers.) What I can't imagine is how this is accomplished at such a tiny scale. Not only tiny, but it has to be exact to mesh with other parts and to spin freely.

    This watchmaking profession is a labyrinth of mysteries. To learn a little only leads to further confusion and questions.
     
  10. Archer Omega Qualified Watchmaker Jul 4, 2021

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    The post can be a separate machined part, or it could be machined out of the plate stock. They are often made of brass, so it can be tough to even see that it might be a separate part once it’s installed and the the plate is machined and plated.

    To explain the pinion term, wheel assemblies on watches are made in two parts generally. The “wheel” portion is typically made of brass or an alloy, and the pinion is made of steel.

    The pinion and wheel both have gear teeth cut into them, and the pinion is the smaller diameter set of the the in the steel part. If you look at the first photo I posted above, the set of teeth in steel are the pinion, and that is pressed into the brass wheel that you can see below it.

    The repairs are not terribly difficult, and really the biggest challenge is finding the center of the hole, and boring out that hole for a post on the lathe. The center of this hole is not in the center of the main plate, so you have to use a specific chuck to center a spot that is off center on the part. This can be done with a faceplate style chuck that can clamp the part off center, or you can use a wax chuck as I did here:

    https://omegaforums.net/threads/watchmaking-crown-wheel-seat-repair.108810/

    There are different ways of picking up the center of a hole like this, so tools like centering scopes that are mounted to the lathe, but a more primitive (but effective way) is using what is known as a wobble stick.

    I know Jim a little from involvement in various watchmaker groups. I don’t know what equipment he has, but sometimes doing this sort of repair yourself isn’t terribly efficient from a business perspective, so if you have someone to do it for you, that can be the best choice. That’s what I did with the above watch, and I know who Jim will probably use, which is the same person I used. He is a watchmaker who no longer services watches, but does nothing but repairs like this and make parts from scratch. He has found a very good space for his abilities, and he is very well equipped for this kind of work. He is also very busy, as the lead time you were quoted indicates.

    Hope this helps.

    Cheers, Al
     
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