Hole depth in a K&D 50B punch?

Discussion in 'Horological Tools' started by SwirlyMaple, Jun 27, 2020.

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  1. SwirlyMaple

    SwirlyMaple Registered User

    Jun 10, 2020
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    Hi, I'm trying to figure out if the teeny tiny hole in my punch for the K&D 50B balance staff remover is clogged or not. If I use a very fine copper wire and insert it into the hole, and bend it over where it bottoms, the hole appears to only be ~0.80 to 0.90mm deep.

    Does anyone know if this is normal, or is that punch clogged? Thanks!

    (And yes I know these generally aren't recommended for removing balance staffs, I'm just trying to complete and restore a K&D set back to tip-top condition as a fine piece of history :))
     
  2. Dushan Grujich

    Dushan Grujich Registered User

    Jun 20, 2003
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    G'Day!

    There are few things to consider:

    1 - Need for a deeper hole in the punch that serves only to knock out a balance staff with already one or two broken pivots.
    2 - If that were important, you would expect that the tip of the punch were cross drilled to enable cleaning if it gets clogged.
    3 - Consider how long are the pivots of the staff when not broken? They rarely get to be as long as 0.40 mm (~0.015")
    4 - Have you ever tried to drill a hole 12/100 mm or 15/100 mm in diameter? Usually holes are drilled no more than 5 to 10 diameters of a drill depending on their diameter, besides drill bits themselves are not much longer than that, unless we are talking of a very special and very expensive drill bits.​

    You have a punch with a hole 0.15 mm in diameter, and you measured something like 0.80 or 0.90 mm, which is about 5 diameters of the the hole i.e. twice a possible pivot length.

    Conclusion is, that everything you are worrying about is in perfect order. BTW, I've checked one that I have and it is just about what you have found.

    Cheers, Dushan
     
    SwirlyMaple likes this.
  3. SwirlyMaple

    SwirlyMaple Registered User

    Jun 10, 2020
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    Hi Dushan, thanks much for the reply! That's solid logic and I'm glad to know all is well. Thanks also for checking yours. Cheers!
     

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