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  1. #1

    Default beryllium copper grade for suspension spring.

    Hello,

    What grade of BC is appropriate for suspension springs? From the research i did, c17200 looks appropriate. However does is need to be half hard or full?

    Thanks
    Dandy

  2. #2
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    Default Re: beryllium copper grade for suspension spring. (By: dandydude)

    Dandy
    In the latest Horological Science Newsletter (2017-2) Robert Matthys advises against the use of BC. The article sites two reasons: a short term humidity speed up problem affecting time keeping and 1 to 3 day lag problem was seen in a bellows pressure correction system. Matthys recommends Phospor Bronze 510, Alumininium Silicon Bronze 642 or Ni Span C type 902.
    Peter

  3. #3

    Default Re: beryllium copper grade for suspension spring. (By: itspcb)

    Quote Originally Posted by itspcb View Post
    Dandy
    In the latest Horological Science Newsletter (2017-2) Robert Matthys advises against the use of BC. The article sites two reasons: a short term humidity speed up problem affecting time keeping and 1 to 3 day lag problem was seen in a bellows pressure correction system. Matthys recommends Phospor Bronze 510, Alumininium Silicon Bronze 642 or Ni Span C type 902.
    Peter
    Hello peter,

    thanks for that. In fact in Robert matthys book accurate clock pendulums, he recommends BC as the ideal material... maybe this is recent finding... thanks for bringing this to my notice.

    regards
    dandy

  4. #4
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    Default Re: beryllium copper grade for suspension spring. (By: dandydude)

    Dandy,
    Yes it is a recent finding, the learning never stops!
    Peter

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    Default Re: beryllium copper grade for suspension spring.

    Quote Originally Posted by dandydude View Post
    Hello peter,

    thanks for that. In fact in Robert matthys book accurate clock pendulums, he recommends BC as the ideal material... maybe this is recent finding... thanks for bringing this to my notice.

    regards
    dandy
    Matthys book revision 2004 page 150 concludes that 642 aluminium silicon bronze is the best suspension spring material. BC is identified on page 149 as "normally the best spring material for general applications."

    Phil
    Last edited by Phil Burman; 04-25-2017 at 07:14 PM. Reason: page number reference

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