Need the dimensions of a Hermle suspension spring

Discussion in 'Clock Repair' started by deloid, Nov 17, 2019.

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  1. deloid

    deloid Registered User
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    Nov 30, 2002
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    I have a 2 wt Hermle clock that is missing the suspension spring. I could use the dimensions so I can make one as I doubt they are available for sale.
    The back plate is stamped 45cm followed on the next line buy 101,9
    The inclusive pendulum rod length is 31cm

    I don't usually work on newer clocks like this and I would like to get a close to original as possible.
    Thanks!
     
  2. JTD

    JTD Registered User

    Sep 27, 2005
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    It would be helpful to see the clock you are talking about.

    Why do you suppose a suspension spring would not be available to buy?

    JTD
     
  3. kinsler33

    kinsler33 Registered User

    Aug 17, 2014
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    I imagine that Mark Butterworth can sell you something that would fit nicely, but I've personally found that suspension springs aren't all that critical. But I do have a question for you, which is to ask how you'd go about manufacturing the ends--the thick parts with hole and with pin--of a home-made suspension spring. It's happened that I've messed up suspension springs without suitable spares, and I've longed to make my own. Do you solder the ends in place?

    Mark Kinsler
     
  4. Willie X

    Willie X Registered User

    Feb 9, 2008
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    Merritt's #P-21.3 or #P-21.4 will do it.
    WIllie X
     
  5. David S

    David S Registered User
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    Dec 18, 2011
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    Mark, I repair or make suspension spring assemblies.

    For the top "brass block", we use a rectangular strip of brass sheet. Tin it on one side with solder, fold in half with tinned side in. Drill holes as required. Prepare the suspension spring material. For bifurcated springs, wrap the spring around a sacrificial wooden dowel and cut out the centre section with a cut off wheel in a rotary tool. Brighten up the ends of the spring that will be in the brass block with sandpaper and lightly tin both sides of the end.
    Insert spring squeeze the folded brass tightly on the spring and heat with a small torch to re-flow the solder. We use a diamond burr in a rotary tool to complete the hole in the spring if necessary.

    cutting spring.jpg finished.jpg

    David
     
  6. Willie X

    Willie X Registered User

    Feb 9, 2008
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    That's a lot of work for $2.
    :) Willie X
     
  7. Uhralt

    Uhralt Registered User
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    Sep 4, 2008
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    Yeah, but I think I would do it in some cases rather than waiting a week for an order to be delivered.

    Uhralt
     
  8. David S

    David S Registered User
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    Indeed it is. However my volume is low and if I don't need anything else the $2 morphs into $20 with minimum order and shipping and one week with no action in my shop while I wait. Besides it is fun and it preps me for the time when a particular suspension spring assy isn't available.

    David
     
  9. kinsler33

    kinsler33 Registered User

    Aug 17, 2014
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    Thank you for that. I, for one, don't expect suspension springs for mechanical clocks--or any parts for mechanical clocks--to be available forever. I didn't realize that the bifurcated springs could be made like that.

    Mark Kinsler
     
  10. Willie X

    Willie X Registered User

    Feb 9, 2008
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    Anyone who works on clocks should have a complete assortment of keys and suspension springs. Cost is around $100 and it's money well spent.

    I also agree that everyone should know how to make this stuff, or be learning how to make this stuff ... just in case there is no choice.

    My 2, WIllie X
     

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