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Recent content by Jim Shewchuk

  1. J

    Watch HANDS CROWN & BALANCE FOR OMEGA 30T2SC

    30 SC T2 was an old reference for Omega caliber 280. Because that same movement could be used in several models, the crown is cross-referenced to the case number, (usually located on the inside of the case back) not the caliber. Unfortunately. I'm unable to help you with specific Omega part...
  2. J

    Accutron Coil Testing

    While physical damage does break these coils much faster, the bending caused by temperature fluctuations will also cause the leads of these coils to eventually break. (over the span of decades, but this failure mode has become significant because the earliest of the Accutrons came out over 55...
  3. J

    Bulls eye glass

    This is just a guess, but since some of the largest pocket watches did come close (I've encountered a single surviving example of a pocket watch case using a 22 ligne glass [49.6 mm / 1.95 inches]) to crossing over into using the smaller end of the clock glasses, I suspect that some even larger...
  4. J

    Bulls eye glass

    As are most of the domed mantel clock crystals I've encountered. The 4mm example referred to a super-thick style of pocket watch crystal I had encountered during sorting those mixed-up crystals. (presumably rarely used because any impact sufficient to break one would likely also severely...
  5. J

    Bulls eye glass

    While sorting some ancient glass crystals that had jumped between bins during a move, I have also encountered the term "Bullseye" used in reference to some pocket watch crystals with a roughly 1cm diameter thicker portion in the middle inner surface. (for "hunter case" pocket watches that had a...
  6. J

    American PW Waltham 1364 vs 1365 Balance staff

    Another quick way to tell on the 1883 model is the shape of the balance wheel spokes: the wheel (1378) that used the large waist 1364 staff had a square center and straight spokes whereas the more popular versions (1376 and 1377 wheels) using the 1365 staff had wheel spokes that tapered...
  7. J

    Obselete Watch Parts Wanted

    Re: Watch Crystals Lee, Seiko parts and crystals are cross-referenced by the case number which is usually an 8-digit number stamped on the outside of case back. In the case of your pictured Seiko, it was 0903-7009. The first part indicates that the watch uses a caliber 0903 movement. In the...
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