Tune Seth Thomas No. 10 Lever Escapement

Discussion in 'Clock Repair' started by weissgoblue, Jan 3, 2020.

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  1. weissgoblue

    weissgoblue Registered User

    Sep 5, 2014
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    #1 weissgoblue, Jan 3, 2020
    Last edited: Jan 3, 2020
    I have cleaned and reassembled the pictured movement and have it running.

    The escapement runs in its "proper" oscillation mode for a few seconds then switches to a "faster" oscillation mode where the balance wheel seems to rotate half the "proper" range for a few seconds before returning to the "proper" oscillation mode. This continues to repeat. Looking in my clock books there is little info on hair spring lever escapements. Perhaps as they are more common is watches?

    I did find some info on setting "beat" but I do not see where lever or escapement offers adjustability and didn't want to force or break anything.

    Attached are some photos and I will soon post a video that shows the escapement behavior described above.

    I would appreciate any help on adjusting the escapement that could be offered

    Thanks, Paul

    IMG_20200102_120658.jpg 1_IMG_20200102_120016.jpg 2_IMG_20200102_120658.jpg 1_IMG_20200102_120016.jpg 2_IMG_20200102_120658.jpg 3_IMG_20200102_120438.jpg 481974-3dd1107623f60eccca1dc61062b48241.jpg
     
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  2. shutterbug

    shutterbug Moderator
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    That is certainly an unusual problem. I believe it is something near the escapement that is creating a power issue. Maybe a pinion gear with a bad tooth. Maybe a bent pivot on or near the escape wheel.
     
  3. Hans_

    Hans_ Registered User

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    Just adding to what Shutterbug said, you might also want to look for a worn bushing.

    Hans
     
  4. shutterbug

    shutterbug Moderator
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    Also look at the pivots of the balance wheel. I can't see them clearly in the pic. Sometimes the cones it sits in are the problem too. Both the cones and the points have to be nicely pointed.
     
  5. weissgoblue

    weissgoblue Registered User

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    Thanks for the suggestions. After some tweaking, it now runs correctly when laid flat - with balance wheel horizontal. When I set it vertical, the behavior occurs. I will look at the balance wheel pivots and the jewels. and see if I find anything.

    Thanks,
    Paul
     
  6. shutterbug

    shutterbug Moderator
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    Yes, that sounds like a friction issue in the balance wheel. Let us know what you find. You might have a cracked jewel.
     
  7. Uhralt

    Uhralt Registered User
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    There are two versions of this movement, one with jeweled balance bushings and one with the more common cones. I think 9but I may be wrong) that yours is the movement with the balance cone screws. These often wear. Try putting the clock on the back and on the front. if there is a major difference in amplitude or the clock stops in one position, the cone on the bottom of the balance wheel staff is to blame. Most of the time the balance staff itself is also worn and rough. The cone part of the balance staff needs to be polished. The inside of the screw cone also needs to be polished. Sometimes it can be done using a toothpick loaded with Simichrome in a drill. After polishing, all residual Simichrome needs to be removed. You can use multiple clean toothpicks in a drill for that. Continue cleaning until the toothpick comes out clean. Don't use water for cleaning. These cones rust very easily and it is hard to get all water out.
    Uhralt
     
  8. kinsler33

    kinsler33 Registered User

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    While you're at it, consider bushing the fork pivots if they aren't jeweled, and inspect the condition of the jewels if they are. The lost motion from loose fork pivots can seriously affect the performance of these clocks, and it's not always apparent that the holes are worn to that extent.
     
  9. weissgoblue

    weissgoblue Registered User

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    My clock has jeweled bushings for the balance wheel, I have looked at them with a 10x loupe but i cannot see much - do I need a higher magnification to inspect them. Cannot tell if they are cracked or worn. I polished the pivots with a 2000 grit paper. do I need something finer to polish it.

    I will set up with better lighting to see if I can get better view of the jewels.

    Are replacements for the Jewels or Hairsprings available?

    Thanks for all of the suggestions

    Paul
     
  10. weissgoblue

    weissgoblue Registered User

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    I will also look at the condition of the fork pivots.
    Paul
     
  11. kinsler33

    kinsler33 Registered User

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    You may not see much. Examine them while the clock is running, or trying to run. They shouldn't look like they're moving at all, for if you see any motion the hole has worn oversize.

    Note that while we might not bush a pivot with side-play less than, say, 1/3 of the pivot diameter, this sort of rule doesn't apply to either the escape wheel or the fork pivots, both of which should be as tight as possible while still allowing complete freedom of movement.

    One bit of experience I've gained through a few years of clock repair is: when a clock in good condition won't run, or won't continue to run, the next step is to re-bush the escapement--that is, the escape wheel pivots and the anchor pivots--even if they look pretty good. It's saved me on several occasions, and I am often in need of saving.
     
  12. weissgoblue

    weissgoblue Registered User

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    I published a video showing typical movement behavior for you to view in case this helps ID what might be wrong.

    Re: pivots: I will look closer at the lever/escapement pivots to look for errant motion/runout. As the balance wheel runs in Jewels, I assume there is no way to tighten the fit without installing new jewels. The jewels seem to fit the balance wheel pivots well but have no experience to base this on.

    The video is on Youtube at the following link:

    https://youtu.be/ni3Mh0xCX2k
     
  13. shutterbug

    shutterbug Moderator
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    That's an old one. Try bending that little wire that intersects with the balance a little more toward the center of that notch it rides in.
     
  14. kinsler33

    kinsler33 Registered User

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    The escape wheel pivots are somewhat loose, as are the fork pivots (although less so.) I can see movement in both of them, and that's motion that you can't afford to lose. Bush them and then re-adjust the escapement.
     
  15. weissgoblue

    weissgoblue Registered User

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    Thanks for the advise, I will rebush the plates and report back. As this is a part time hobby for me it may take me some time to get back.

    Many thanks, Your trained eye is much better than my untrained one, as I don't see movement. I will put the video on repeat and sit down and/or watch the movement for a while tosee if I can see what you are seeing.
    Thanks
    Paul
     
  16. Uhralt

    Uhralt Registered User
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    I see very little amplitude of the balance wheel. Would it increase dramatically when you push the wheel next to the escape wheel manually? If it does, you may have a power loss issue somewhere in the train that must be addressed. This movement with its two springs has a lot of power, so where does it get lost?

    Uhralt
     
  17. kinsler33

    kinsler33 Registered User

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    What I saw was a very slight movement of the escape wheel pivot within its hole in the plate, and something similar but of smaller amplitude in the lever pivot. Again, I was looking at the pivots, not the escape wheel or lever themselves. Also note that there may be some artifact in the video or perhaps in my wits that's making me see this movement. (You'll also want to look at the opposite pivots on these parts. ) The object is to reduce to an absolute minimum any side-shake of these particular pivots in their holes, for any lost motion in these will be magnified in the motion of the balance wheel.
     
  18. weissgoblue

    weissgoblue Registered User

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    Sorry it took some time to get back to you as I work full time as an engineer - clock repair is only a hobby. At your suggestion, I rebushed the movement, as you saw in the video, there was movement in the lever, escapement wheel as well as the 3rd and 4th wheels. It now seems to be running properly. I ran overnight keeping time with 1 minute which I should be able to remove with the adjustment lever. Many thanks for your help on the first lever movement that I have restored. Paul
     

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