Main spring problem

Discussion in '400-Day & Atmos' started by Dells, Oct 21, 2019.

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  1. Dells

    Dells Registered User

    Oct 18, 2019
    30
    2
    8
    Male
    Country Flag:
    Hi all new to forum but had lots of clocks for over 50 years but one of them has a problem with the main spring, it Is a Jahresuhrenfabrik the one with the two elephants on back plate, it runs fine and keeps very good time about 1 minute a month ( good for a torsion clock ) but it will only work when fully wound ( it will run for 2-3-4 months then stop I then have to wind it again but it will only wind 2 or three clicks, I have tried letting the spring down and winding it again but no better.
    Can anyone please help.
    Thanks Dell C3A9748D-D143-424F-B5CB-0AD96202DDF5.jpeg
     
  2. KurtinSA

    KurtinSA Registered User
    NAWCC Member

    Nov 24, 2014
    3,082
    87
    48
    Aerospace Engineer (Ret.)
    San Antonio, TX
    Country Flag:
    Region Flag:
    Dell -

    Welcome to the message board! When someone finds the answer and posts here, I too will be happy! I have a number of clocks like that. I have joked to friends "the only clocks I have that run for 400 days are my 1000-day clocks".

    As I've surmised in my cases, there's something wrong with the movement and/or escapement that will run under full power, but will stop when the power level drops off. Could be some excess friction in some pivots, bent pivots, some binding in the train, improperly lubricated mainspring, worn out mainspring, fork not set correctly...see where I'm going? Could be lots of things. I have a Kundo clock that I've been working with for nearly two years and it will only run for a week to a month. I did everything I could and figured it was an old mainspring. I replaced it and that didn't solve the issue, so I'm back at square one.

    So, as you can see, I'm no real help, but I'll be interested in what others say.

    Kurt
     
  3. Wayne A

    Wayne A Registered User

    Sep 24, 2019
    63
    8
    8
    Retired, process controll systems
    Country Flag:
    Region Flag:
    #3 Wayne A, Oct 21, 2019
    Last edited: Oct 21, 2019
    Something wrong somewhere! Well I used that line allot back when I was working.. Anyway like Kurt said above, so may things can be marginal but together can add up to a problem. Now my impression in a short time working on these torsion spring clocks is there fairly simple machines but are quite picky in setup which makes it interesting. One thing I want to see is that an unwound spring when wound one click will power the escapement if you rock the anchor by hand, drag is the enemy.
    When you unwound the spring did it make any noise or have any jumps in torque? I've noticed on my homemade spring winder that at times a spring's torque can vary dramatically as you slowly wind and unwind it from sticking/slipping or so called sticksion which happens when very flat objects get very close and form a vacuum that sticks them together. The homemade winder allows you to feel the spring torque since it has no anti reverse rotation device. Some clocks probably would stop when the spring torque hits one of those low spots.
     
  4. Dells

    Dells Registered User

    Oct 18, 2019
    30
    2
    8
    Male
    Country Flag:
    Thanks for the reply’s
    When I let down the spring it unwinds very smooth through my hand, and if I wind it back up just a few turns it will not run only when I wind it fully will it run but after running 2-3-4 months it will only wind 2 or 3 clicks.
    Dell
     
  5. whatgoesaround

    whatgoesaround Registered User

    Jan 22, 2008
    380
    13
    18
    Male
    science teacher
    south carolina
    Country Flag:
    Region Flag:
    Sounds like something is wrong in the movement. Check Kurt's posting above
     
  6. Harry Hopkins

    Harry Hopkins Registered User
    NAWCC Member

    Nov 16, 2011
    542
    37
    28
    Retired Instrument Technician
    Mason, IL
    Country Flag:
    Region Flag:
    There is lots of good advice above.. as you can see there are many things that can cause your clock to stop before 400 days. I think one of the most overlooked reasons a well maintained torsion clock will not run as long as intended is setting the fork height too high for maximum rotation instead of maximum overswing. Ideally you will want the fork as low as you can get it without having any escapement flutter but this gives less rotation and many people prefer to see a bigger swing. The escapement is at its most efficient when overswing is maximized.
     
    Kevin W. likes this.

Share This Page