Figuring the wheel sizes, tooth count of a clock I admire and want to build.....

Discussion in 'Clock Construction' started by doc_fields, Aug 18, 2019.

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  1. doc_fields

    doc_fields Registered User

    Sep 29, 2004
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    I found this clock on snclocks.com, here is the link:

    VR-384 6 Month Duration Bodenstanduhren - SNClocks

    I've meticulously counted the wheels and pinions that I can see, but some can't either BE seen, or are only partly visible. Here are the counts I do have:

    Barrel:
    168 teeth, 16 pinion teeth
    Center wheel:
    194 teeth, 18 pinion teeth
    First wheel:
    144 teeth, 8 pinon teeth
    Picture #8 of 17 is where I'm not sure to figure.
    The top wheel is the minute wheel, and I think 72 teeth.
    The intermediate is 72 teeth.
    The center wheel has 72 teeth.
    The escape wheel has 60 teeth, but the pinion that drives it is hidden behind the plate. How many teeth would be on that escape wheel is what I need to know, and finally................

    How can I figure the wheel diameters with what is given in the pictures and tooth counts so I can use the right cutters or modules?

    With a complete wheel count, I know I could then figure pendulum length, correct?

    The reason I like this clock is because everything is in an upside down configuration, which I like, AND, it is a 6 month duration in one winding.

    I may have left some details out, but any help would be appreciated! Thanks!................................gary

    Post Script: I can't post any of the pictures because they are owned by snclocks.com.
     
  2. sharukh

    sharukh Registered User
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    Why not ask Stephen ?

    Sharukh
     
  3. doc_fields

    doc_fields Registered User

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    I had a nice long visit with him a couple of months ago and enjoyed it.

    As I remember, I asked him if he had any repair notes on this clock detailing what I asked about here, and his reply, as best as I remember, was no, but he figured by looking closely at the photos, it could all be figured out.

    So, short answer, yes, I did.
     
  4. Allan Wolff

    Allan Wolff Moderator
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    I'll take a shot at the easy part first.
    The seconds hand attaches to the escape wheel. From the dial, it appears the escape wheel makes one revolution every 2 minutes. With 60 escape wheel teeth, that means it requires a 1 second pendulum, which has a length of 39.15 inches. As a check, a 30 tooth escape wheel will make one revolution every minute with the same pendulum. Also, the tick rate from the video seems to match the rate of my grandfather clock which has a one second pendulum.

    Have you figured out the other hands? Is the center hand the hour hand? Looks like it connects directly to the second wheel. The top subdial only goes up to 4.
     
  5. doc_fields

    doc_fields Registered User

    Sep 29, 2004
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    Allan;
    The top dial is the hours, the middle is the minutes, and the bottom of course is the seconds, and as Steve says on his subheading of the first picture of the dial , "...the lower hands chapter ring covers two minutes!"

    I don't know if it is evident or not, but the hour hand apparently has a hole through the center of the hand in order to wind the clock. I thought at first you had to remove the hand, but upon closer magnification, it appears to be a hole, with the hour hand slip fit over the hour pipe underneath.

    If the escape wheel is making one revolution per minute, and the second wheel has 144 teeth, then 12 teeth would be needed to turn a 12 tooth pinion on the escape wheel to make one revolution of that wheel, correct? If true, then that would complete the tooth count of the wheels and pinions of the movement. Next would be to figure the diameters of the wheels, how to go about that?

    Allan, if you would when you read this, please change in Post #1 the "first" wheel to the "second" wheel, please. I tend to forget that sometimes.
    Thanks very much!...........................gary

    BTW: Here is another clock built by Franz Walter, and very similar to this one.

    Untitled Document
     
  6. Jim DuBois

    Jim DuBois Registered User
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    Jun 14, 2008
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    With 60 teeth on the escape wheel and a seconds pendulum, it makes a revolution in 2 minutes, not one.

    Regards wheel diameters and metric module, one needs to be decided to calculate the other. So, sometimes others let available wheel cutters determine the diameter or conversely determine how big the great wheel could be with the available real estate. Sometimes something as simple as the capacity of an available lathe or wheel cutting setup, or for that matter available brass stock to make the parts. It is often useful to determine one cutter size and use it for all the wheels and one size for pinions and set up tooth counts and ultimately wheel diameters using 2 common cutters.
     
  7. doc_fields

    doc_fields Registered User

    Sep 29, 2004
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    Jim;
    Thank you for the clarification, I actually see and understand now what you mean. I think then that is how I'll proceed.

    However, I believe I may have it wrong on my guess of a 12 tooth pinion on the escape wheel to drive it, or would 6 be correct to get the two revolutions then?

    I really DO appreciate all the responses. Thanks for taking the time to enlighten me.................................gary
     
  8. Jim DuBois

    Jim DuBois Registered User
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    Generally, in high-grade clocks, which this one certainly is, pinions would not be 6 leafed. Generally, I would expect it to be 8 or 12 leaf, not 6. 6 leaf pinons have too much-sliding friction according to some experts. Some won't use 8 leaf and older regulator plans often call for 12 or 16 leaf just because of the sliding friction can allegedly be minimized in the higher leaf count pinions. I have not dug into your photos or the counts you have made, just playing back general regulator theory.
     
  9. doc_fields

    doc_fields Registered User

    Sep 29, 2004
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    Jim;

    After looking back at some of the wheel counts, I've really messed up! Hopefully, I can edit everything and get a little clearer idea of what is there. Sorry to all who have noticed this, I guess I'm not paying attention too well..............................gary
     

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