Strike issue with 8-day brass strap movement

Discussion in 'Clock Repair' started by jboger, Oct 30, 2019.

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  1. jboger

    jboger Registered User

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    Members were a great help when I incorrectly reassembled the strike side of Terry movement. I had an alignment issue on the pin ont he 4th wheel: a couple of levers had to be in the right position in order for the strike train to work properly, that is, strike the hour and stop.

    Now I am looking at an 8-day strap movement from an Upson, Merriman & Co triple decker. I bushed and put the clock in beat. It now runs well. But I have similar strike issues: the strike side does NOT stop, but lets the weight drop entirely to the bottom of the case.

    There is one less wheel in the train (compared to a Terry movement). That is, there is no fourth wheel with a pin. The fourth wheel is the fan and it has a wire that sticks out. The third wheel has a cam with a single slot.

    What are the initial conditions that I need when I put the movement back together? Any help with this would once again be greatly appreciated.

    IMG_0613.jpg
     
  2. leeinv66

    leeinv66 Moderator
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    I'll move this over to clock repair.
     
  3. R&A

    R&A Registered User

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    I would need more pictures of the train I don't have this movement to look at to tell you
     
  4. kinsler33

    kinsler33 Registered User

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    Some old clocks used the fly (fan) as a warning wheel. As the hour approaches, the lifting cam first releases the strike train but then almost immediately swings a wire in the way of the strike fan to stop the train again. At the hour, that wire drops down and allows the strike train to run.

    I'm forgetting the names of the strike train wheels here, of course.
     
  5. jboger

    jboger Registered User

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    Yes, kinsler33, that is how it works. It struck me that the fan is what ultimately releases the strike train. I note that the count wheel is released about 10 minutes before the hour. I thought this might be the problem, but not anymore. Before I post any more pictures, I want to check to see that the lever that stops the fan--or should stop the fan--is working properly.
     
  6. shutterbug

    shutterbug Moderator
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    Some count wheel clocks use the cam as the stop. If that were the case, you'd see a steeper cam slot with a straight side to stop the train. If that is how yours is designed, the straight part might be worn and needs to be filed straight again. Or, the stop lever might not be falling far enough into the slot.
     
  7. Jim DuBois

    Jim DuBois Registered User
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    #7 Jim DuBois, Oct 31, 2019
    Last edited: Oct 31, 2019
    I suspect you have a minor timing problem in the strike train. You are most likely a tooth or so off in the timing between the count wheel on the main arbor and the cam on the third wheel that lifts and drops the count hook itself and also provides the lock to stop striking. Simply put the count wheel hook has to be free to drop cleanly into the slot at the same time as the cam allows the drop. If it is a tooth or so off the hook will hit the side of the slot and often not lock. Runaway strike. Here is an example where a past "craftsman" reformed the hook instead of retiming the train properly. Admittedly, it can be a pain to get it right. One photo shows the cam that both lifts the count hook and locks the train, just perhaps to add clarity to the discussion. This style movement does not have the wire stop on the fan wheel. There is a pin on the 3rd wheel that stops the train from rotating further at warning.

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  8. jboger

    jboger Registered User

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    Here are some pictures of the dismantled movement. Look at some of the wires/levers, how bent they are. I find it hard to believe that they left the original manufacturer in that condition, that the manufacturer couldn't set the wires on the arbors with nearly the correct positions and angles. Tell me otherwise if such is the case. I think to bend the wires back to what I think were their original positions. Is that a bad idea?

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  9. Jim DuBois

    Jim DuBois Registered User
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    Generally speaking one would expect the wires to be reasonably straight as originally formed. I tend to straighten them out in movements I restore/repair. That said, returning them to what we expect to be correct may well open any of us to a lot of tuning, readjusting, and increasing our vocabulary. If it works as is but just misses the stop pin on the 3rd wheel then I would think a tweak or minor adjustment to correct that single issue would be logical. To straighten them all may be proper but also painful to start. Of course, it will be educational too!

    I recently bought a clock with a similar movement to yours where the owner had done the straighten everything routine. He had ended up throwing away all the strike control wires, so I go the clock for almost no money, and I had a partial movement on hand with proper parts. Lucky on my part.

    If you are patient you can certainly return it to proper configuration as I see it.
     
  10. kinsler33

    kinsler33 Registered User

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    The proper strategy is to first, learn how the mechanism works. That is, you'll have two levers, each with perhaps three extensions radiating from the central shaft. Learn the purpose of each of these extensions. For example, the count lever will have an extension that touches the count-wheel teeth, plus another extension that's lifted by the warning lever, plus an extension that rides on or near the cam on the third strike wheel. The warning lever will have a U-shaped extension that's pushed by the wire L on the minute-hand arbor, plus an extension that contacts the count lever, plus at least one extension that interacts with a pin on one of the strike wheels.

    And so until you understand quite thoroughly the function of these various extensions, the standing orders are to (1) bend nothing (2) file nothing and (3) cut nothing.

    This all sounds horrible, but you'll get used to count-wheel clocks soon enough. There may be wear on the levers from a century of use, but if they're bent it was due to the ministrations of some kid who died of old age in 1912.

    M Kinsler
     
  11. shutterbug

    shutterbug Moderator
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    I wouldn't bend anything until I could see how they perform in the clock. They were bent for a reason, and probably a good one. Bending them now might open a whole can of worms when trying to get them to work together again.
     
  12. Jim DuBois

    Jim DuBois Registered User
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    In the majority of cases, the wires are reformed by people who don't retime the strike trains properly when they reassemble the movements. Then things get bent so as to allow some semblance of proper function. Usually wear is not a cause. Movements like the one in this thread complicate life for us all by not having any original makers indexing marks on the strike train. Then, another manufacturing limitation comes into play in that MANY of these strap movements, by several makers, require the drums to come off the great wheels to restring them. So, as we might say in other forums, compounding felonies that may lead us further astray. Many of these period strap movements have had later modifications of redrilling the barrels so as to allow restringing assembled, and slightly later clock makers incorporated drilled barrels too. I have perhaps a couple dozen examples of strap movements by several makers and about 1/2 of them have solid barrels requiring complete disassembly to restring. I have two of the Upsom/Barnes/Terry's now and they both have the solid barrels.

    Nice casting flaw in the one barrel I might add. I like the example of the two-click wheel model too. Both time and strike sides are like that and it appears as if it was made that way. The pewter/zinc drums are a frequent point of failure also.

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