Problem Hands

Discussion in '400-Day & Atmos' started by MuensterMann, Jul 8, 2019.

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  1. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    I have some 400-day clocks that work, but then after a period of time (days to months) - especially if I move the hands to correct the time, the clock stops and will not go. Most times I remove the hands and the clock runs. Hands back on - it stops. So, I am thinking that the problem is that little cupped washer behind the dial on the main arbor. Am I right? If so, does it mean that it lost the curve of its cup, and thus it needs to be bent slightly to increase the curve? Just trying to figure it out to get several of my clocks running again!
     
  2. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    When the clock stops, where is the minute hand? Is it always on the 0:30 to 0:60 side of the dial? If you say when the hands are back on, the clock stops, I wonder if there's a power problem and it can't raise the minute hand past 0:45.

    Typically that cupped washer or tension washer just adds tension to the canon pinion so the hands don't just flop to 6:30 but turn with the center arbor.

    Kurt
     
  3. Harry Hopkins

    Harry Hopkins Registered User
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    Nov 16, 2011
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    The curve of the cupped washer is ok as long as it gives the minute hand enough tension so it doesn't flop. The most common problem associated with the cupped washer that would cause a clock to stop is if the washer is touching the front plate... there is a shoulder on the center arbor that is slightly on the outside of the front plate that the washer should sit on. If the hole in the washer is too large or for any other reason the washer is touching the front plate the clock will almost stop at some point.
     
  4. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    Hmmmm. Thanks for telling me the main function of the cupped washer. I have one clock the worked for months. Then one day I adjusted the time and no more go. Hands off - go. Hands on - no go. There is some force that the hands are adding that is enough for no-go.
     
  5. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    Beyond what Harry mentions, with the tension washer dragging on the front plate, you should probably look at a conflict somewhere else...unless you're mainspring is not powerful enough to raise the hands. As an extreme situation, say that the canon pinion and hand were glued to the center arbor...with the hour pipe and intermediate wheel free to turn, there's no reason the clock wouldn't run with the minute hand fixed...you just wouldn't be able to adjust the time. So, the tension washer provides the resistance to keep the hand from flopping but lets you turn the canon pinion to adjust the time. The reason for the clock stopping is likely somewhere else.

    Whenever, I get into these situations, I end up taking off the dial and putting the motion works back on one piece at a time. I then monitor how the clock runs with each new piece. Then I figure out where the conflict is.

    Kurt
     
  6. Allan Wolff

    Allan Wolff Moderator
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    Mar 17, 2005
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    The next time it stops, lightly wiggle the hour hand to make sure it is not rubbing on the minute hand. It could be that the hour hand collet is not pushed on far enough. A little friction between the hands near the arbors can be enough to stop a clock.
     
  7. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    That's why you take the dial off to resume testing. You can visually inspect and see the conflict.

    Kurt
     
  8. MuensterMann

    MuensterMann Registered User

    Mar 23, 2008
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    Thank you! I just fiddling with one of my Kundo's, on the smaller side, and I believe the friction was at the hands. I readjusted the hands - pushing the hour hand in a little bit. It seemed to have done the trick - but I am testing now to make sure. Then, I will check the others that give me problems - which include a Schatz carriage (again on the smaller side).
     

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