4 wheel going train in 30 hour clock with no seconds hand

Discussion in 'General Clock Discussions' started by DeanT, Apr 16, 2017.

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  1. DeanT

    DeanT Registered User

    Mar 22, 2009
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    Hi All,

    Attached are some photos of the going train of a 30 hour clock dating to 1680's to 1690. It has a 4 wheel going train and doesn't have a seconds hand so 3 wheels would have been sufficient.

    For those that like numbers:
    Great Wheel 60 teeth wheel
    Centre Wheel 60 teeth wheel/12 leaf pinion
    Third Wheel 48 teeth wheel/8 leaf pinion
    Escape Wheel 30 teeth wheel/6 leaf pinion

    30/6 x 48/8 x 60 =1800 so standard second pendulum.

    I've also attached a photo of anchor which is small and only spans 5 teeth of the escape wheel.

    There is also a photo showing the lack of collet on wheels. Instead the wheel is fixed via a square arbour. This is an early feature as most clockmakers were using collets by the last qtr of the 17thC.

    The picture of the dial shows the individual minute markers and lack of half qtr markers which is often seen on clocks pre 1680. C&W says these spandrels were often used past 1695 but I've seen a photo of a Tompion dated 1676 which has C&W No.5 spandrels as well.

    Any ideas on why the clockmaker would use an extra wheel in going train? Is the shape of the anchor usual?
     
  2. novicetimekeeper

    novicetimekeeper Registered User
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    D&H examples of anchors don't shed much light, and their reasoning for 4 wheel trains other than the seconds hand is to improve the minute hand stability on two handed clocks.

    The do have lovely pictures of arbours like yours showing the short leaf pinions associated too.
     
  3. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    I suspect that the person that made the clock was not
    good at math. He copied the train from a second hand
    clock.
    You have to remember many of these people didn't get
    the same level of education that we do today. Figuring
    ratios is complicated for many today, even knowing how to
    do the math.
    He'd make a train that was known to work.
    Tinker Dwight
     
  4. jmclaugh

    jmclaugh Registered User

    Jun 1, 2006
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    I can't think of a good reason for a 30 hour clock without a seconds hand to have 4 wheels in the train and I don't see how a fourth wheel does much to improve the stability of the minute hand but I'd be happy to hear why. There would have been plenty of three train movements for someone to copy so the idea the maker copied a 4 wheel train clock seems a little unlikely but who knows.

    Btw Dean the movement has cleaned up nicely.
     
  5. novicetimekeeper

    novicetimekeeper Registered User
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    Darken and Hooper make the same point that it wasn't until the advent of the long pendulum that anybody needed to be that bothered about ratios, they just needed something to work. It all became rather more critical when the second pendulum came into being.

    The maker of this was clearly a lantern clock maker with the techniques used and Dean's wheel count is quite low which suggests that even if an engine were available the wheels were not originally designed to be cut by one.


    D&H say that 4 wheel trains like this were only made by quality makers, and everything about this clock suggests quality.
     
  6. novicetimekeeper

    novicetimekeeper Registered User
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    From Darken & Hooper, English 30 hour clocks 1600-1800 published by Penita books 1997

    "Although the three wheel going train was to remain the most widely used for 30 hour clocks, during the last quarter of the seventeenth century an alternative (the centre wheel train, see plate 8/5) was introduced, a "short duration" version of an 8 day going train. For use only for two-handed clocks, it had the advantage that the minute hand was securely located (no slackness or shake) and that the escape arbour could be extended to carry a seconds hand."

    In my experience seconds hands are pretty rare on posted frame clocks, I've only seen two or three and one was by Clement so that's understandable. I don't know why this would be, but I do know London makers adopted plated movements for 30 hours fairly quickly. Perhaps posted frames became just a provincial thing too fast.
     
  7. MrStretch

    MrStretch Registered User

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    There is a 5:1 ratio on this clock between the great wheel and the centre pinion, which a more efficient arrangement than the typical 8-day clock with a 12:1. This suggests that the clockmaker knew what he was doing. If he had copied the ratios from an 8-day he would have ended up making an 8-day clock!
    Also, it's bs that ratios weren't important until the seconds pendulum. The very first clocks we have any record of had count wheel striking mechanisms. Good luck figuring that out without a decent knowledge of gear ratios. What about Didondi 'S planetarium or Jost Burgi who made some clocks with seconds Hands in the 16th century?
     
  8. Ralph

    Ralph Registered User
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  9. novicetimekeeper

    novicetimekeeper Registered User
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    I think you misunderstand, the important thing was to get the clock to run to time but the ratios could be anything to achieve that, and as a result there was no standard 3 train clock. When the seconds pendulum was introduced it meant that you needed the escape wheel to rotate once per minute if you were going to stick a second hand on it. That had never been an issue before.

    - - - Updated - - -

    That is quoted extensively in D&H.
     
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