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  1. watchknut New watch + Instagram + wife = dumbass Aug 22, 2018

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    I have a Signal Corps with a cal 13 SO movement, and it needs a new mainspring.

    My watchmaker is having a hard time sourcing one.

    Hoping someone can point me in the right direction. I cannot find any info on the size of the mainspring.

    Thanks!
     
  2. Canuck Aug 22, 2018

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    Perhaps someone else will know what movement you need the spring for. But I sure don’t. Show us the movement, please. And what is it about the mainspring that is so peculiar to the watch that a generic replacement won”t do? Help us to help you.
     
    Edited Aug 23, 2018
    airansun likes this.
  3. watchknut New watch + Instagram + wife = dumbass Aug 23, 2018

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    Here is the movt, I thought it was a cal.13 SO
    B0AE06ED-E55A-431E-82F0-1B47962950B1.jpeg
     
  4. Canuck Aug 23, 2018

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  5. watchknut New watch + Instagram + wife = dumbass Aug 23, 2018

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    Thank you sir!!!

    Huge help...and I agree, it is out of his wheelhouse, I figured it would be easy, but apparently not.
     
  6. Archer Omega Qualified Watchmaker Aug 24, 2018

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    Your watchmaker should be able to measure the existing mainspring to find the size for the new one. Ends can be modified to work in some cases without a lot of trouble.
     
  7. watchknut New watch + Instagram + wife = dumbass Aug 24, 2018

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    The problem is that another watchmaker, long story, removed the mainspring and put in an incorrect one, so none to measure.

    Appreciate all of the help on this!
     
  8. Archer Omega Qualified Watchmaker Aug 24, 2018

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    Well, once you correctly ID the movement it will be easier. I would take the Ranftt database with a large grain of salt - often has errors in technical information.
     
  9. ChrisN Aug 24, 2018

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    From this book, assuming it's a cal 13 (not sure of the difference in SO and NN) although I'm not sure how you're identifying it:
    spring1.jpg
    spring2.jpg

    You need a FAMA FLEX 385...


    That might be hard so, here are the dimensions:D
    spring3.jpg

    You've probably got sufficient here if it is a slightly different calibre. At least your watchmaker can check the barrel diameter and height agree before ordering a generic spring. He can also calculate if the length is correct if you assume the strength (thickness) is good because of the space it will occupy in the barrel (basically half of what's available - it uses this when it is relaxed or wound).

    Cheers, Chris
     
    eugeneandresson and Archer like this.
  10. watchknut New watch + Instagram + wife = dumbass Aug 24, 2018

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    Killer! Thanks bud. Really appreciate @Canuck and @Archer helping well.