What can you tell me about pendulum weight for anniversary clocks?

Discussion in '400-Day & Atmos' started by gvasale, Jul 9, 2005.

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  1. gvasale

    gvasale Registered User
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    Mar 30, 2005
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    I played with one of my clocks today and noticed that the pendulum for this one is very heavy (Schatz 49 with auxiliary spring) compared to other clocks with the 4 ball pendulum. Also, it looks like it may run with a different spring than specified (time will tell). Any observations here?
     
  2. gvasale

    gvasale Registered User
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    Mar 30, 2005
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    I played with one of my clocks today and noticed that the pendulum for this one is very heavy (Schatz 49 with auxiliary spring) compared to other clocks with the 4 ball pendulum. Also, it looks like it may run with a different spring than specified (time will tell). Any observations here?
     
  3. John Hubby

    John Hubby Senior Administrator Emeritus
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    The Schatz 49 original pendulum weighs about 12-1/2 ounces, one of the heaviest 4-Ball pendulums made. For comparison, the 1949 Kundo pendulum weighs 11-1/2 ounces. Kundo also made 4-Ball pendulums that look just like the 1949 version but weigh less, one at 10.5 ounces and one at 8.5 ounces.

    What does this mean? In principle, the less the pendulum weighs the thinner the suspension spring required to keep the clock to time. That's why the Schatz 49 uses a 0.0040" spring and the Kundo 1949 version uses a 0.0032" spring. Remember that both clocks are running at the same 8 beats per minute!!

    There is also a relationship to suspension spring length, but it is much less important than the thickness of the spring and the weight of the pendulum. The main thing is to check FIRST to see what the Repair Guide recommends, and start from there.

    John Hubby
     
  4. Kevin W.

    Kevin W. Registered User

    Apr 11, 2002
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    Hi John and others. I am working on a Schatz model 49 clock. It has two weights made of lead, and two weights made of steel, the steelweights way less than the lead ones do. Can this affect time keeping? Thanks.
     
  5. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    What is the current total weight of the pendulum? Typically Schatz 49s have weights around 12.5 - 12.8 oz. As John indicated, weight does affect the time keeping...nominally Schatz 49 suspension springs run 0.004" thick.

    Kurt
     
  6. Kevin W.

    Kevin W. Registered User

    Apr 11, 2002
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    Thanks Kurt, i was just going to weigh the pendulum. I checked and it does have a .004 inch thick susp spring.
     
  7. Kevin W.

    Kevin W. Registered User

    Apr 11, 2002
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    I just weighed it on a digital diet scale and i get 11 ounces even.
    I am thinking instead of changing the suspension spring could i not add weight to the pendulum in some way, perhaps washers.
     
  8. KurtinSA

    KurtinSA Registered User
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    I had the same idea for a pendulum I had...I didn't find enough room under the cover to fit as much weight as I needed. Seems like you'll need some dense material to get another 1.5 oz. More than likely, you'd be better of doing one of two things. First, it would be best to come up with two new lead weights. Second, figure out what size suspension spring you need to use. Doing the first brings the clock back to "original" and the next repair person won't be scratching their head. I suppose if you were able to cram enough weight in there, that person would probably realize what's going on. The second one will present a head scratcher to the repair person...I guess seeing the weight difference might give them a clue that something else is not standard.

    Kurt
     
  9. Kevin W.

    Kevin W. Registered User

    Apr 11, 2002
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    As i said the suspension spring is 4 thou thick, as the book calls for. I am thinking of adding weight, I prefer to add weight, and not change the suspension. I would prefer not to look for heavier balls. As its a customers clock, and he wishes to get it sooner than later. Thanks for your help Kurt.
     
  10. MartinM

    MartinM Registered User

    Jun 24, 2011
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    As it's obviously a mashup of parts, it might be best to see a picture of the pendulum to be sure just what it is you're dealing with.
     

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