Servicing Schatz with Maintaining Power 3rd Wheel

Discussion in '400-Day & Atmos' started by KurtinSA, Sep 14, 2019.

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  1. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    I'm going to work on a Schatz Model 49R plate 1291A built 10 53. It has the maintaining power 3rd wheel. It didn't come to me with the side wings as documented in TorsionTimes. I'm trying to decide if/should I disassemble the small spring barrel to clean, etc. I have a few of these barrels in my spares, one has a spring with the outside hole broken off, so it is unusable. I've been playing a bit with that spring. I've wound it back inside the open barrel, but at the slightest provocation, it will jump out of the barrel!!

    Anyway, is there any benefit to opening the barrel for servicing? For cleaning with any solution such as in a ultrasonic tank or other soaking solutions, water will get inside the small barrel. That would need to be thoroughly dried out otherwise the spring would rust. I'm considering not doing that and just focus on polishing the pivots.

    As for polishing the pivots, are there any issues with mounting the arbor (including the sealed barrel) into my lathe with collets on the arbor to polish/burnish the pivots? Seems like the spinning will create some inertia on the spring barrel and wind up/out the internal spring. Should I tape the barrel to the arbor in some way to temporarily fix it to the arbor while spinning in the lathe?

    Thanks...Kurt
     
  2. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    I had another spare barrel with a cover on it...didn't know what was inside. So, I pried off the cover and this is what I found. This helps explain what was in Vol 21 of the TorsionTimes. I thought there was a hole in the outside end of the spring, but as seen, the end is bent back over a small rod of some kind and planted in the stub of brass that sticks out from the side of the barrel. I guess with all the pressure from the spring coil, it holds it all together.

    Barely visible is the hole in the inner loop of the spring which catches on the circumference of the arbor.

    Kurt

    MaintainBarrel.jpg
     
  3. KurtinSA

    KurtinSA Registered User
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    Bolstered by doing that, I decided to pop the cover on the barrel that came with the clock. I carefully extracted the arbor which I can now clean and polish. I could see that the inner spring had some oil on it. Normally, as with the main spring barrel, I would burnish the inside part of the hole of the cover and barrel. But I don't think I'm going to worry about that.

    My thinking is that while the barrel should turn around the arbor to provide this "extra" power during operation, if it were physically stuck, it would be acting just like a solid wheel/arbor that Schatz supplied if one asked to have the maintaining wheel replaced for some reason. They found out it really didn't work as advertised, was complicated to produce, so would just give a solid wheel as a replacement. But with the arbor physically out, I can easily chuck it in the lathe and polish the pivots.

    Kurt
     
  4. Uhralt

    Uhralt Registered User
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    Sep 4, 2008
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    I'm struggling with the rationale for this wheel. A mainspring in a barrel has maintaining power during winding all by itself. Is the purpose of the wheel to keep power as constant as possible while the clock is running down, or what is it?

    Uhralt
     
  5. KurtinSA

    KurtinSA Registered User
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    Nov 24, 2014
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    Uhralt -

    That seems to be the idea behind it. As I'm sure we've all seen, as the main spring power gets near the end, the time keeping of the clock is affected. So, the small spring would begin to add to the power from the main spring towards the end of the year running.

    That said, John Hubby mentioned some testing that was done and it really didn't help with the timing keeping, but certainly added to the length of the time the clock would run. Schatz decided not provide spares of this wheel if a customer asked for a replacement. Due to the complexity of the wheel and the time it took to make it, it just wasn't worth the effort given the limited effect it had. So, Schatz just provided a "regular" wheel if needed.

    A recent TorsionTimes shows they were mostly made in 1953 but there were runs made in 1954 and 1955.

    Kurt
     

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