plate #1381A

Discussion in '400-Day & Atmos' started by Randall Chinn, Oct 21, 2019.

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  1. Randall Chinn

    Randall Chinn New Member

    Oct 21, 2019
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    I have been collecting anniversary clocks for a couple of years and repaired several. This last clock I purchased runs fast. I retarded the pendulum as far as it will go but he clock still gains 1 hour in 24. I did replace the torsion spring with a Horolovar (.058mm). The clock runs great otherwise. Any advice would be greatly appreciated. Thank you in advance.
  2. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    Aerospace Engineer (Ret.)
    San Antonio, TX
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    Welcome to the message board! Could be an issue with the weight of the pendulum...could be the suspension spring is not exactly 0.058mm (0.0023"). If you could upload a picture or two of the clock, back plate, and the pendulum might be helpful.

    Your clock is gaining about 2.5 seconds per minute. Your spring may be slightly thicker than required. A rule of thumb is that changes in the thickness of 0.0001" results in 4 sec per minute swing rate. So, one thing you could do is thin your current spring a touch. To do this, you would need to remove the spring and also take off the fork as well as the top block. Then using thin strips of 600 grit sandpaper, slide the spring between the sandpaper from the bottom block through the end of the spring while pressing with your fingers. Probably best to use something flat like popsicle sticks to create an even pressure. But after a number of strokes, say 10-15, reassemble without the fork and see how the swing rate is. For this clock, it should swing for 10 beats in 60 seconds. You might want to try this timing technique before disassembling and get a time for 10 beats. For your current situation, it was be 10 beats in less than 60 seconds. Try the thinning process a bit at a time to sneak up on the right swing rate over the 60 seconds.

    Looking forward to seeing some pictures!


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