Hermle 340-020A Hairspring Balance out of range

Discussion in 'Clock Repair' started by bchaps, Jun 29, 2005.

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  1. bchaps

    bchaps Registered User

    Dec 16, 2001
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    Mountain Top, PA
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    I received a client's clock (Hermle 340-020A hairspring balance) that "gained time" right out of the box. After much frustration with the Furniture store where purchased, it ended up in my shop. The movement was clocked at 9500 BPH while it should have a normal rate of 9000. I observed the hairspring was "sticky" and assumed magnetism or oil. The spring was cleaned in One-Dip, eliminating the sticky condition and I was confident the fast-rate issue was resolved. With the regulator in mid-range, it now clocked 9072 BPH...better, but still a gain of 12 minutes per day. Only by moving the regulator to the most extreme slow position have I been able to get the balance to run at 9000. Balance action isn't great - about 180 degrees total oscillation. After searching this forum, I saw another similar complaint from several years ago. Other than poor hairspring pinning by Hermle, can the fast rate be caused by anything else?

    Thank You, Bill

    When Fried and de Carle haven't discussed it, ask the NAWCC Message Board!
     
  2. bchaps

    bchaps Registered User

    Dec 16, 2001
    1,130
    13
    38
    Mountain Top, PA
    Country Flag:
    Region Flag:
    I received a client's clock (Hermle 340-020A hairspring balance) that "gained time" right out of the box. After much frustration with the Furniture store where purchased, it ended up in my shop. The movement was clocked at 9500 BPH while it should have a normal rate of 9000. I observed the hairspring was "sticky" and assumed magnetism or oil. The spring was cleaned in One-Dip, eliminating the sticky condition and I was confident the fast-rate issue was resolved. With the regulator in mid-range, it now clocked 9072 BPH...better, but still a gain of 12 minutes per day. Only by moving the regulator to the most extreme slow position have I been able to get the balance to run at 9000. Balance action isn't great - about 180 degrees total oscillation. After searching this forum, I saw another similar complaint from several years ago. Other than poor hairspring pinning by Hermle, can the fast rate be caused by anything else?

    Thank You, Bill

    When Fried and de Carle haven't discussed it, ask the NAWCC Message Board!
     
  3. LaBounty

    LaBounty Registered User
    NAWCC Life Member

    Aug 29, 2002
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    Mitchell, NE
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    Hi Bill-

    I'd say look at how the hairspring is vibrating in the regulator slot. If it is beating hard against one side the balance action is being limited. It should beat evenly against both sides. The adjustment is done back at where it is pinned by flexing the hairspring one way or the other.

    Good luck with it and let us know what you find.
     
  4. bchaps

    bchaps Registered User

    Dec 16, 2001
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    The hairspring is not vibrating thru the regulator slot but stays against the inside edge. I double checked the rotation and it is producting about 240 degrees total swing. Does vibrating thru the regulator improve rotation?

    Bill
     
  5. Viv Rose

    Viv Rose Registered User

    Apr 19, 2005
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    As LaBounty states - it must beat equally against both sides. If it is permanently resting against one side this will act like a brake.
     
  6. Robert M.

    Robert M. Registered User

    Nov 20, 2004
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    Bill,Let your power down on the time train and see if your pins are aligned dead center of the pallet.If not just take a jewelers screwdriver and tweak the hairspring collet a bit to re-align it.One other problem I had a while back was the fork touching the ring on the hairspring assembly at the point of entry.I didn't even notice it until I looked at it through a loupe.Initially I couldn't get my movement to drop below 10,000 but after I tweaked the fork it worked fine.I had another Hermle with the same problem that for the life of me I couldn't get below 9500.I got so frustrated I finally e-mailed Mark Butterworth.He said it could either be an escape wheel out of round or a bent pivot.Seeing that I had it apart I figured bent pivot and sure enough the third wheel had a bit of a tilt to her.I corrected that and she was fine.Those Hermles DO have some soft pivots unlike their American counterparts
    I just thought I'd pass along some of my own experiences with Hermles.Hopefully they may be of some help to you.Good luck with your problem.
    Respectfully,Bob Fullerton
     
  7. LaBounty

    LaBounty Registered User
    NAWCC Life Member

    Aug 29, 2002
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    Hey Bill-

    Bob brings up a good point. Adjusting the way the hairspring acts between the regulator pins will slightly alter the beat of the clock. It shouldn't make any difference but it is certainly something to watch for. And the clock needs to be in beat in order to run well.

    And Viv worded the situation much better than I did. If your hairspring is staying on one side of the regulator it will certainly act as a brake. As the balance rotates, it will pull the hairspring taught against the inside of the regulator and cause the balance action to stop prematurely.

    Another way of looking at it is in the way the regulator functions. Having the hairspring hard against one side of the regulator is the same as pinning it there. The hairspring is essentially shortened. But, if the hairspring beats equally on both sides of the regulator pins, it is one length when touching and another (longer) when it is free and between pins.

    So, having the hairspring beat evenly between the regulator will increase the balance action and it will probably go from the 240 deg. it is now to better than 360 deg. This should slow the clock down to the point you can regulate it.

    Let us know if it works!
     

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