Koma vibrations

Discussion in '400-Day & Atmos' started by Dells, Nov 2, 2019.

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  1. Dells

    Dells Registered User

    Oct 18, 2019
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    Coach builder
    In the cotswolds
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    Hi all just put a new torsion spring on a Koma but I have noticed that when the pendulum is going clockwise the fork vibrates but it is very smooth going anti-clockwise, anyone have any suggestions as to why.
    Thanks Dell
     
  2. Kevin W.

    Kevin W. Registered User
    NAWCC Member

    Apr 11, 2002
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    I work at the Veritas Tools machine shop.
    Nepean, Ontario, Canada
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    Never experienced that problem before, hope someone has a answer for it.
     
  3. etmb61

    etmb61 Registered User
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    Oct 25, 2010
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    Retired Avionics Technician
    Mascoutah, IL
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    Does the escape wheel advance several teeth as it vibrates?
     
  4. Dells

    Dells Registered User

    Oct 18, 2019
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    Coach builder
    In the cotswolds
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    No it only moves one tooth and I rocked the anchor prior to fitting the new torsion spring.
    Dell
     
  5. Wayne A

    Wayne A Registered User

    Sep 24, 2019
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    I'll throw out a few ideas.
    -There is some small vertical and horizontal movement in the pin/fork contact point each beat, so check for a notch in the fork or pin on the side making contact during clockwise rotation.
    -Verify that torsion spring clamps are square to the spring and positioned square in the hanger and pendulum.
    -Proper clearance between pin and fork 1-2thousandths.
     
  6. Dells

    Dells Registered User

    Oct 18, 2019
    47
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    8
    Male
    Coach builder
    In the cotswolds
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    Will check again tomorrow but I could not see any problems and used a feeler gauge to check gap in fork 3 thousands.
    Dell
     
  7. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    San Antonio, TX
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    Typically using a piece of regular paper as a "feeler gage" is all that's needed.

    Kurt
     
  8. MartinM

    MartinM Registered User

    Jun 24, 2011
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    Medical Insurance Systems Analyst
    El Dorado, CA
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    Sometimes, this happens when the clock is slightly out of beat and the fork is a bit low on the suspension spring.Also check that the pin on the anchor is vertical and not tilted toward the back plate.
     

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