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  1. #1

    Default measuring pendulum

    Hi im ordering new pendulum for french clock I will need to alter length can any one advise me at which points on pendulum do i measure from and to.approx 248mm thanks kenny...

  2. #2
    Registered User Scottie-TX's Avatar
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    Default Re: measuring pendulum (RE: chubbybull)

    Typically pendulum length is specified and measured from the point the spring flexes at the chops to apx. center of pendulum. That could mean total pendulum length to bottom of bob apx. 26cm. Wow. That's a long pendulum for a frenchy.

  3. #3

    Default Re: measuring pendulum (RE: Scottie-TX)

    Quote Originally Posted by Scottie-TX View Post
    Typically pendulum length is specified and measured from the point the spring flexes at the chops to apx. center of pendulum. That could mean total pendulum length to bottom of bob apx. 26cm. Wow. That's a long pendulum for a frenchy.
    Thanks very much Scottie..
    -> posts merged by system <-
    Quote Originally Posted by Scottie-TX View Post
    Typically pendulum length is specified and measured from the point the spring flexes at the chops to apx. center of pendulum. That could mean total pendulum length to bottom of bob apx. 26cm. Wow. That's a long pendulum for a frenchy.
    Im going of meadows+passmores conversion. the bottom of my clock back plate is stamped 9.2 and its telling me 248mm.Dose seem long..

  4. #4
    Principal Administrator John Hubby's Avatar
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    Default Re: measuring pendulum (RE: chubbybull)

    Scottie, if the numbers on the back of the movement are "9 2" then CB's pendulum length measure is correct. That's only 10 inches or thereabout and I've seen a number of French mantel clocks (especially the large marble case ones) with pendulums that long.

  5. #5
    Registered User Scottie-TX's Avatar
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    Default Re: measuring pendulum (RE: John Hubby)

    Oh please: I never cast aspersions on his measurement. Fact, I have here a large dial frenchy that entertains me daily right next to my work area with a open brocot. It's pendulum is ten inches.

  6. #6

    Default Re: measuring pendulum (RE: Scottie-TX)

    248 is an impressive number, but its only in mm so still not very large.

    9 pouce 2 linge is about the longest pendulum I can remember to have seen on these movements.

    The simplest way to calculate from Pouce/Ligne indication to mm is:
    left number, multiply by 12.
    add the second number.

    multiply by 2,256

    done. the result is in mm.

    one important notice is that by law of 1812 the length of the French Pouce was altered; clocks made in the timeframe 1812 to 1840 should be calculated with a multiplication factor of 2,31.

    All this is effective pendulum length, so it might be smart to calculate the mm pendulum lenght to BPM and hook up the timer, instead of trial and error.

  7. #7
    Registered User Scottie-TX's Avatar
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    Default Re: measuring pendulum (RE: antiekeradio)

    Only timer I got here is for eggs.

  8. #8

    Default Re: measuring pendulum (RE: Scottie-TX)

    trial and error it is, then (for me too, by the way)

    still it saves counting teeth and calculating for those who do have means of measuring BPM

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