Jewel size

Discussion in 'Watch Repair' started by mdk1970, Sep 13, 2019.

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  1. mdk1970

    mdk1970 Registered User

    Apr 20, 2012
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    I have a question i have a 1923 16s bunn special 21j. I replaced the ballance hole jewels which are .13 and the i had the ballance restaffed with the pivot being .11 is the combination correct? Thanks in advance to any help
     
  2. Dave Coatsworth

    Dave Coatsworth Forums Administrator
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    Feb 11, 2005
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    That's really too loose but may work. The optimum is .01 difference.
     
  3. mdk1970

    mdk1970 Registered User

    Apr 20, 2012
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    It does work but now its like 3 min fast in 24hrs and i added wieght slowed it down a little but i really dont wanta start manipulating the watch it was 1 sec off a day a remarkable watch i wanted to get more input before i go further thx for ur help and response
     
  4. mdk1970

    mdk1970 Registered User

    Apr 20, 2012
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    I also noticed the hairspring pins were bent apart to 3x the spring size so i tightened them up a bit I'm an amature and I'm just scratching the surface again thanks for ur help i dont have a timing machine im synchronizing it with a quartz sad but true
     
  5. gmorse

    gmorse Registered User
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    Jan 7, 2011
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    Hi mdk1970,

    I think you'll find the document in this post by DeweyC interesting and informative.

    Regards,

    Graham
     
    musicguy likes this.
  6. Skutt50

    Skutt50 Registered User

    Mar 14, 2008
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    This will speed up the movement quite a bit! Could very well be the three minutes you found.......

    The three hairspring sized gap is a bit too much but may have been made by an earlier watchmaker to get the watch to run slower.

    The link Graham gave you will enlighten you but if this is one of your first watches, be careful before you make any changes......
     
  7. GeneJockey

    GeneJockey Registered User
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    Mar 2, 2012
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    What kind of amplitude are you getting? I would not be concerned about the rate until amplitude at full wind is above 250, preferably above 270.
     
  8. Rick Hufnagel

    Rick Hufnagel Just Rick!
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    Oct 25, 2018
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    If the watch ran great before hand, why add weight? The problem lies somewhere else. Adding weight is covering up the real problem and throwing off any adjustments.

    I'm no expert.. but it seems the correct size balance jewels will be the place to start.
     
  9. mdk1970

    mdk1970 Registered User

    Apr 20, 2012
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    Thank you for all your knowledge and i am gonna start with replaceing the jewels with .12 next is finding them any good suppliers im familiar with a couple online and ebay doesnt offer anything at the time
     
  10. mdk1970

    mdk1970 Registered User

    Apr 20, 2012
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    I want to keep this timepiece as original as possible and i would really appreciate any further knowledge when needed and i WILL need it lol thx again
     
  11. Rob P.

    Rob P. Registered User

    Dec 19, 2011
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    There's a website that cross references parts for Elgin's.

    http://www.elginwatchparts.com/

    If you enter your grade # it takes you to a second page with all the parts with part #'s for them. Lower on that page you can inter the part # of the parts you're looking for and see what other watches also use those parts.

    To get the grade # (NOT model #) of your Bunn you can use this link:

    [ELGIN] Pocket Watch Serial Numbers:   Date, Grade, Jewels

    Once you know the parts interchangeability, it helps when looking for junker parts movements on places like fleabay.
     

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