English PW Balance staff English fusee

Discussion in 'Watch Repair' started by praezis, Jun 13, 2019.

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  1. praezis

    praezis Registered User

    Feb 11, 2008
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    I have to change the mentioned balance staff (1st time this type). It looks like it is a simple straight or tapered staff. The balance spoke has a riveted brass sleeve that contains the staff.

    EnglFusee1.jpg EnglFusee2.jpg EnglFusee3.jpg

    How should I remove the old staff. If tapered, in which direction?
    Thanks for help,

    Frank
     
  2. Jerry Kieffer

    Jerry Kieffer Registered User
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    May 31, 2005
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    Frank
    Based on the third photo, it appears that the staff could have only been installed from the bottom of the balance. I would remove the roller and drive out from the top of the balance down. I would also dimension the brass sleeve first, in case something really strange happens. It can then be easily remade.

    Jerry Kieffer
     
  3. Jerry Kieffer

    Jerry Kieffer Registered User
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    Frank
    I am a little late on this , but on second look, it appears that the staff has a hub that the roller is seated on. If so, it would then be difficult to support the brass sleeve when removing the staff. This can be resolved by using a staking tool roller removing accessory per attached photo. The arms can reach behind the hub and support the sleeve.

    Jerry Kieffer

    fullsizeoutput_3eb.jpeg
     
  4. praezis

    praezis Registered User

    Feb 11, 2008
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    Jerry,
    thank you for being engaged in my problem and for your hints!
    After posting I found that exactly my question had already been answered in 2015 here.

    Both of you advised to push the staff to the bottom. My measurement however showed a staff diameter of 0.56 at the upper end of the brass sleeve and 0.55 at the lower end. Assuming a straight tapered staff I was tempted to push it to the top, but no movement.
    Eventually I could remove the staff to the bottom.
    Bal_fus2.jpg

    A strange double tapered staff appeared: the part in the brass sleeve was roughly square shaped.
    Bal_fus3.jpg

    In advance I had removed the roller that came loose with a nasty frightening cracking noise, but there was no damage in any way.
    Bal_fus1.jpg

    Hours later this work was finished.
    Bal_fus4.jpg

    Frank
     
  5. Jerry Kieffer

    Jerry Kieffer Registered User
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    Frank
    I am happy it worked out for you. It looks great.

    The most unusual staff I have ever had, had a roller that was one piece to the staff itself with a triangle roller jewel in a triangle hole.

    In this case, if you did not have a staff, I am assuming that you machined or cut a replacement staff. Personally, if it had ran true when chucked on the square, I may have been tempted to repivot it as it appears to have the dimensions that would support such a repair.

    Jerry Kieffer
     
  6. praezis

    praezis Registered User

    Feb 11, 2008
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    Jerry,
    yes I made a new staff.
    0.11 mm pivots are beyond my drilling possibilities, my limit is 0.20.

    Frank
     
  7. Jerry Kieffer

    Jerry Kieffer Registered User
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    Frank
    Micro drilling is of course another topic by itself.

    In this case, I would have also machined a new staff due to its basic design. However had I repivoted it for whatever reason, it would have been done per the attached sketch.
    When repivoting, I rarely Repivot the actual size of the pivot, but some what larger. I then machine down too size that assures a round straight pivot centered to the staff or whatever.

    Jerry Kieffer

    fullsizeoutput_3ef.jpeg
     
  8. praezis

    praezis Registered User

    Feb 11, 2008
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    Jerry,
    I know that micro drilling is one of your favorite topics and I like your postings and amazing ideas.

    Recently I had to replace twice the pallet staffs of PWs as above. One got the pivot drilled, the other staff was turned. I found the drilling not so much faster than the other method. With all the involved extra work amazingly it always takes twice the time that I expected before.

    Frank
     
  9. Jerry Kieffer

    Jerry Kieffer Registered User
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    Frank
    I would agree that a typical pallet arbor can be turned or machined in about the same time as repivoting. Personally, I only repivot where original strength, accuracy, appearance and function can be maintained while minimizing time and effort.

    Jerry Kieffer
     

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