A Little Story About Reliability & Accuracy

If you take a look at the ‘comments’ on the Movement Table page, you’ll see a story from Brian, who bought a watch for his mother in 1972. The watch was used on a daily basis up to a couple of years ago. Brian has measured the watch against his atomic clock over the last few days and found it to be within a couple of seconds per day! Impressive or what? And….the watch has never been serviced!! Pretty remarkable and an impressive tale of reliability and accuracy.

The watch is a Cosmostar V2, a fine little high beat movement running at 28,800 beats per hour. Here’s my example:

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10 Responses to A Little Story About Reliability & Accuracy

  1. Hi Stephen,

    Perhaps you can help me with this one. Is there another model number for these two Cosmostars?


    A friend is helping me track down a part and the source is asking for a model number similar to this: BF0540-51E

    What do you think?


    • sweephand says:

      Hi – thanks for visiting my blog. I don’t have model numbers for those two Cosmostars I’m afraid, although the case numbers you’ve given would usually be the best ones to use for parts. The model number you’ve quoted is a much later type as seen on quartz models – the Cosmostars would have something like this: 64-3637 (that’s from a Cosmostar, case number 4-660102). If you Google the case numbers you’ve got, preceded by Citizen, you’ll find some parts and their numbers listed by Boley, Germany (Boley is owned by Citizen). They reference some case parts, although I understand this doesn’t mean they stock them.

      If movement parts are needed I’d have thought a donor watch is the likeliest source these days,


      • Thanks.

        Do your old catalogs with the Cosmostars show a different type of number? Even other models from the same time period might give a clue.
        Enviado desde mi dispositivo BlackBerry® de +Móvil

        • sweephand says:

          The catalogs use the case number and what I assume is a catalog number, see this scan from the 1971 catalog:

          A couple of model numbers for you for the Cosmostar V2 are 64-3611 and 64-3637. Parts for the movement itself will be the same for all the 6600 movements, but different for case parts of course.


  2. Hi Stephen,

    Using the numbers I gave you, can you find them in your catalogs or
    are they online for me to search?

    I can also send photos.


    • sweephand says:

      The ones you gave me are not in my catalogs I’m afraid. Do you know which part is needed?


      • The crystals.

        I see that you had slightly different Cosmostar model numbers in your previous response. 64-3611.

        How did you find that? I did not see them in the catalog.

        Perhaps that is the issue?

        Thanks again.

        Enviado desde mi dispositivo BlackBerry® de +Móvil

        • sweephand says:

          The model numbers are stamped on the case backs but aren’t shown in the catalogs, and the ones I gave you are examples from the watches I have in my collection – not all watches have these numbers though, some only have the case number, e.g. 4-660439. Using the case numbers you gave me, I found the part numbers for the crystals (from Boley.de):
          4-660439 – crystal is 54-50540
          4-660145 – crystal is 54-50210
          All crystals from this age of watch start with ’54’.


          • Hi Stephen,

            Many thanks.

            Indeed, I found those part numbers as well. No longer in stock. Borel doesn’t have them either. I have a friend who knows some folks at Citizen looking for more information and specs. I hope to have some replacements made. Either in Sapphire or Mineral. Plastic would be an acceptable alternative but would rather try for the best and most original.

            What is amazing is that these little machines still run as well as they do after all these years.


            • sweephand says:

              It’s great to hear that you are going to get crystals made for them. They are great watches, the high beat movement is a gem, and good ones seem very accurate and reliable,


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