Bill Stoddard

Suspension Springs for Schatz and Kundo Miniature 400 Day Clocks

On several previous posts, I noted that some Schatz miniature 400 day clocks (model 53 movement) needed a 0.0024 inch thick suspension spring (whereas the Horolovar 400 Day Clock Repair Guide specifies a 0.0023 inch spring).

I just experienced this again – this week I repaired a Schatz “London Coach” 400 day clock (which has the model 53 movement). The clock ran too slow with a Horolovar 0.0023 inch spring. With a 0.0024 inch spring, it keeps good time.

I measured the thickness of the 0.0023 inch springs, and they are closer to 0.0022 inch thick. It may be that a batch of springs were made too thin, or were mislabeled.

I experienced the same thing with a Kundo miniature 400 day clock this week.  With a “0.0023 inch” spring, It needed to have the pendulum regulated almost all the way toward fast to get the clock to keep time. A 0.024 inch spring allowed the clock to keep good time with the regulator near the center of its adjustment.

Conclusion: if a Kundo or Schatz niniature 400 day clock loses time with a 0.023 inch Horolovar suspension spring, install a 0.0024 inch spring.


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8 comments

  1. I’ve found that an imperfect suspension spring can stop the clock – I would try a new one. A spring that was previously twisted may be bad.

  2. Hi. My shatz 53 refuses to run. I know my way round clocks and despite everything looking ok it won’t continue to run.
    I’ve adjusted everything but now wondering on suspension spring. If as suggested the wrong spring has been attached would it still be run (you suggested it would run slow if 0023 fitted)? Or will a ‘wrong un’ stop the clock. One thing I noticed on getting this clock was that the suspension spring was severely twisted, I’ve straightened out that twist.
    Ta for any advice
    Mike

  3. I just went through this with a Kundo 9″ miniature with the loose bottom block pin. Somehow I got to thinking that it called or a .0022 spring and when I ran the clock it ran too slow. So now its’ back to the drawing board, with a .0024 Worse yet I have lost my measurements. I know better. I always mark and measure my springs before take them apart. Good luck gong on line and finding the correct wire length. I can probably go to the library and get the book. If not then I am going to have to just break down and get the book.

  8. I have a Schatz 1000 Day, Series 1040, “54” Movement. Date: 5/55
    Would this have a .0023″ suspension spring?
    Should I buy a .0024 spring just in case the stock spring runs slow?
    I measured the broken suspension spring at .0020, but this is with a vernier metric caliper, so highly inaccurate. Thanks.

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