Chronograph Q: What is a scale to 20 on outer ring on dial, and mechanical question

Thread: Chronograph Q: What is a scale to 20 on outer ring on dial, and mechanical question

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  1. #1
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    Chronograph Q: What is a scale to 20 on outer ring on dial, and mechanical question

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    Does anyone know what the 20 ring is for?

    Also, the center wheel, the wheel on the Y shaped bridge, the one that should connect when I activate the stopwatch function I think it's supposed to connect with the wheel next to it that is continually running, but not only does it not connect with that wheel, leading the chrono function not to work, but it is very loose.

    Also, the upper pusher just starts the chrono. To stop it, you press the lower pusher.

    Thanks

  2. #2
    Zenith Forum Co-moderator
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    Re: Chronograph Q: What is a scale to 20 on outer ring on dial, and mechanical question

    1. The 20 scale is a telemetric scale. The speed of sound being what it is, three seconds is one km at sea level and normal temperature. Therefore, if you hear a noise 6 seconds after you see the event (e.g. thunder after lightening), the source is 2km away. Originally developed for battle when you saw cannonfire and then heard the noise. It is also a cheat - the scale should go round a little more than 20 seconds (nearly 21) since it takes slightly less than 3 seconds per km but most makers aren't accurate!

    2. The movement is by Landeron and this is the normal way their chrono buttons work: start at 2:00 but stop at 4:00

    3. If the chrono doesn't work and something is loose, you need to get it serviced; if the worst comes to the worst, it will even require some parts replacement.

    Hartmut Richter
    Last edited by Hartmut Richter; June 15th, 2012 at 23:24. Reason: Editing my wrong figures - 2x3 is 6. not 5, you oaf!!!

  3. #3
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    Re: Chronograph Q: What is a scale to 20 on outer ring on dial, and mechanical question

    Thanks a lot!

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