Help Seth Thomas #120 strikes too often

Discussion in 'Clock Repair' started by geiger, Oct 20, 2019.

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  1. geiger

    geiger New Member

    Oct 20, 2019
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    I have a Seth Thomas mantle clock with a 120 movement I am an amateur and after a little investigating decided undertake (thinking I had nothing to loose) the disassembly, cleaning, and re-assembly of the movement because it wasn't working even though 2 clock repairmen had worked on it after which it ran for a few days, then only for a few hours.
    I didn't do any mechanical work on the parts,, but just cleaned, re-assembled, and oiled.
    It actually runs now! (surprised as to why now? ) but have a problem- it strikes on the hour and half hour correctly, but also strikes once at ~8 minutes before the every hour.
    I figure I must have assembled something in the wrong position or something?
    Any help would be appreciated.
     
  2. Uhralt

    Uhralt Registered User
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    Sep 4, 2008
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    Welcome to the Message Board! Probably your hammer is lifted when the clock has stopped striking. Then, when the clock goes into warning, the extra strike is released. Make sure that the hammer tail is between two pins (and not resting on one) when the clock has stopped striking.

    Uhralt
     
  3. shutterbug

    shutterbug Moderator
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    Oct 19, 2005
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    You may be able to reach into the movement and bend the hammer tail a bit without having to split the plates again.
     
  4. geiger

    geiger New Member

    Oct 20, 2019
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    #4 geiger, Oct 21, 2019
    Last edited by a moderator: Oct 21, 2019
    Thanks for the insight. That is exactly what was happening.
    It took me a few minutes to figure out how to release the gears necessary to move the pin position a little. Now everything works fine.
    It ran all night for the first time in a long while! Hopefully it will go all week. So far, so good.
    Thanks again.
     
  5. Uhralt

    Uhralt Registered User
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    Good job! Glad I could help.

    Uhralt
     
  6. R. Croswell

    R. Croswell Registered User

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    That's what typically happens when a clock that's been "worked on" wasn't disassembled and properly cleaned. When taking a clock to someone for service it is important to ask if the movement will be disassembled for cleaning, what is the estimated cost, and what is the warranty. Any reputable clock repair shop should make things right when the repair fails in "a few days" or even a few months.

    Glad you got the strike issue resolved.

    RC
     
  7. Clocks In The Grove

    Clocks In The Grove Registered User
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    Hard to believe that two CLOCK REPAIRMEN could not fix this the Seth Thomas No, 120. Did the fact that the plates are round throw them off? The one odd thing about the clock is that the main springs are in cans, boxes, containers or what ever you want to call them. If someone like op could get the clock running by taking it apart and cleaning it why couldn't 'clock repairmen' fix it. This is not the first time someone has asked for help because the repair person could not or did not fix the clock. If one take money for repair them he/she needs to give back a working unit and needs to stand behind the work. That is what I think.
    ..Bob..
     
  8. shutterbug

    shutterbug Moderator
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    I was discussing repairing clocks with a man who repairs clocks in another State. I lamented the number of Dunken Swisher's in the business, and he freely admitted that he's one of them. "I don't take them apart unless I have to" he said. So there you are o_O
     
  9. Bruce Alexander

    Bruce Alexander Registered User
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    Feb 22, 2010
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    Welcome the the NAWCC's message board geiger! Glad you got the issue straightened out.

    Congrats on your first disassembly, cleaning and reassembly!

    (Great call Uhrait!)

    The Seth Thomas 120 is nice, straight-forward, reliable, good time-keeping little mechanism.

    If you decide to work on additional clocks, regardless of which strike count mechanism is utilized, I've found it helpful to work bottom up with positioning the Strike Train Gears. You want the minute arbor to be just past the top of the hour, and starting with the Star Wheel, make sure the strike hammer has just dropped. That is the point that you want the strike train to go into lock so working from the star wheel up to the lock wheel (sometimes the lock and warning wheel are one in the same). Position all of the gears so that the conditions for lock are met. I think that the 120 has a combined lock/warning wheel so the warning run is set by design but some movements require you to set the warning run. That can be tricky sometimes.

    You want the strike hammer to be completely at rest, and you want the Hammer to stay at rest when the Strike Train goes into Warning.

    The 120 uses a Rack and Snail Strike Counting Mechanism so when I set up one of these, I normally set it up to strike 12 times. When that is set up properly, the other hours should count out fine, but check them anyway. Especially note if the Count transitions from 12 to 1 normally.

    A mistake that may be seen with these movements is loss of the plate spacing washer on the bottom pillar. I think that some versions may not require the washer, but if it is supposed to be placed, there may be power problems with binding of the great wheels if it is left out of reassembly.

    There are a lot of threads discussing this movement in the archives.

    Again, welcome and congrats.

    Bruce
     

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