Norman Saati & Co., Geneva

Discussion in 'Chronometers' started by doug sinclair, Dec 5, 2013.

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  1. doug sinclair

    doug sinclair Registered User

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    This name popped into my head this morning. Initially, I didn't connect the name with Horologica. Saati produced a one-wheel marine chronometer circa 1895. In 2011, one of these sold at auction for quite a chunk of change. After searching the MB index, the BULLETIN index, and Google, I came up with one item on this company. And that was the listing for the closed auction. I am wondering if anyone knows anything about Saati. Was the one-wheel chronometer an experimental unit? Did he produce more than one of these? What else did he produce? Anyone?
     
  2. doug sinclair

    doug sinclair Registered User

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    Re-opening a three year old thread. There was no response. Here are pictures of Saati's one-wheel marine chronometer. Anyone know anything about it? (Unable to upload pictures, sorry, But in deed, interesting!)
     
  3. doug sinclair

    doug sinclair Registered User

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    I was unable to upload the pictures (wrong file type), but the images are available on line.
     
  4. Tom McIntyre

    Tom McIntyre Technical Admin
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    Doug, I am almost certain that Skinner and Robert Cheney have granted permission to use material from their archives in our discussions so long as we acknowledge the source. Here is the description of the lot as sold. The hammer price with premium was $13,035.

    I remember taking a tour of Skinners with Robert and looking at this lot before the sale. It was fascinating, but seemed to be too much of a project for me to undertake either as a collector or certainly as a craftsman. I would have been interested in it as an unfinished document but could not really afford that.
    886293.jpg 886293_view 02_02.jpg 886293_view 03_03.jpg 886293_view 04_04.jpg 886293_view 05_05.jpg
     
  5. doug sinclair

    doug sinclair Registered User

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    Tom,

    Thanks for that. Seems as though this "revolutionary" development which had the potential to revolutionize marine chronometers, ended up not catching on with other chronometer makers! I was interested that it is a lever escapement, not a detent. I wonder if it was reliable enough, and accurate enough, to have ever served as a chronometer.
     
  6. Tom McIntyre

    Tom McIntyre Technical Admin
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    The catalog description calls the escapement a lever, but the balance must beat very very slowly i.e. 2 bps.

    The large wheel in the center is the escape wheel and the arrangements of arms and pallets across the top must provide the drive. I suspect that the action on the inclined plane screw on the escape wheel arbor generates about as much friction as a gear and pinion would but it is of a different sort so maybe that is the advantage. It looks like the pallets acting on the screw shaped portion are alternatively positioned to provide the driving force and somehow hop back up to the top as each main wheel tooth moves to the next position and the alternate arm reaches the bottom.

    If the balance beats 4 bps (240 bpm) there would need to be 240 teeth on the escape wheel to give the one minute period of the center second hand.I do not think there are nearly that many, but there might be 120 teeth on the escape wheel. The lever does look like a standard form, so I cannot see how it could be impulsed on alternate beats. I never saw the piece actually operating that I recall. I think I would have noticed 2 beats per second.

    Of course my counting could be way off. It really is interesting and perhaps some chronometer experts could chip in with their views
     
  7. doug sinclair

    doug sinclair Registered User

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    #7 doug sinclair, Oct 19, 2016
    Last edited: Oct 19, 2016
    Tom,

    Considering that the escape wheel would only advance 1/2 a tooth at each beat, I think the 120 number makes sense. It would take 240 beats of the balance for the escape wheel to make one revolution. It seems that the banking screws are both on the same side of the anchor. One toward the counterpoise end, and the other toward the fork end.

    I see that Saati nor his mechanism is mentioned either in Gould or in Whitney. So perhaps the sales catalog used a bit of hyperbole in the auction listing! Interesting nonetheless.
     

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