Heco 400 day losing ~4 hours per day

Discussion in '400-Day & Atmos' started by earl08, Apr 16, 2018.

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  1. earl08

    earl08 Registered User
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    Jun 29, 2016
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    I have a coehler 400 day. Suspension spring on it had a kink. .0025 in spring on it has now been replace. It is losing 4 per day, I suspect the spring that was on it is incorrect. Can someone tell me what spring should be on it? thanks in advance.

    400 day 1.jpg 400 day.jpg
     
  2. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    According to the repair guide, it should have an 0.0032" spring.

    Kurt
     
  3. earl08

    earl08 Registered User
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    thanks Kurt. kinda figured it was not right. proably why it would up in the family's storage. FWIW I did check the spring size with 2 different tools digital caliper and micrometer.
     
  4. KurtinSA

    KurtinSA Registered User
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    I've not gotten the second handshake on how to properly measure the thickness of a suspension spring and I have three micrometers and a digital caliper (typically not enough resolution). I basically trust the packages I get for being the stated size. If the clock doesn't keep time within regulation, then I have to figure out what spring to go to next. The best situation would be that if it were too fast, it's possible to thin the existing spring to slow it down...I've been fairly successful when having to do that. If the clock is too slow, all that can be done really is to go with a thicker spring.

    Kurt
     
  5. Harry Hopkins

    Harry Hopkins Registered User
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    I agree with Kurt that .0032 is correct for your clock but from my calculations a jump from .0025 to .0032 would result in your clock running approximately 11 hours per day faster. I am guessing the kinked spring you measured was not a genuine Horolovar spring. The Repair Guide spring sizes will only work for the Horolovar springs so keep that in mind when ordering your new .0032 inch spring.
     
  6. shutterbug

    shutterbug Super Moderator
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    For every .0001" of thickness change, the rate will increase (or decrease) by 4 minutes per hour. Thicker runs faster.
     
  7. Tim Orr

    Tim Orr Registered User
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    Good afternoon, Earl!

    Pretty far out there, but given it's such a huge time loss, might it not be the case that the escapement is "fluttering" so badly that the clock is actually gaining 8 hours instead of losing 4? As Harry suggests, the "right" spring ought to make the clock run 11 hours a day faster than it appears to be running now.

    Best regards!

    Tim Orr
     

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