Forums Latest Auctions Members

The insides of a Zenith Captain Chronometre Caliber 71

  1. Geezer

    Geezer Sep 7, 2019

    Posts
    44
    Likes
    94
    Hi Everyone,

    A short while ago I made a post about a watch purchase from a dealer that was described as “serviced”, but actually wasn’t.

    The watch in question is a Zenith Captain Chronometer with Cal. 71 movement. This is a bit of a grail watch for me, especially one in the condition this one is in. The case is razor sharp and the milled hourglass on the caseback looks like it was machined yesterday.

    20190826_110230.jpg

    As there doesn’t appear to be much information about this caliber on the internet, please find some general information and some pictures from the “real” service below.

    So won’t talk in length about the background of the movement. In short, the caliber 71 is a caliber 133.8 with a date function. This date adds several components to the movement and changes the mainplate somewhat (more about that below). According the Ranfft, about 14.000 were made between 1954 to 1957. Some with chronometer certification and some without. The frequency of this movement is 21.600 vibrations per hour.

    Opening up the case of the watch we find the movement in pretty much perfect condition. No scratches or signs of mistreatment at all on the movement. I have the suspicion that this might be the first ever service. It’s a time capsule with the only remark being that the flat-polished screws for the automatic winding mechanism bridge are slightly marked from a screwdriver. All other screws are pristine. The movement looks completely dry though, and a bit dirty (in the picture you can notice the hair on the oscillating weight).

    20190826_190646.jpg

    This particular model has the movement fit inside a casing ring and uses an additional steel spring that pushes against the caseback. Other versions can be seen that have a spring fixed on the barrel bridge that presses against the caseback and keeps the movement in place.

    Removing the movement from the case we can see the dial with crisp printing. The hands also look untouched although they are covered in a layer of dirt.

    20190826_190834.jpg

    20190904_121931.jpg

    Taking a look at the back of the dial we see the Jean Singer signature and the 18k stamp.

    20190826_191924.jpg

    Now it’s time to take a look at the dial side of the movement. In this movement the hour wheel is directly driving the date driving wheel, instead of having an additional wheel in between. This means that the calendar wheel turns anti-clockwise at midnight, which is not so common.

    Clean copy.jpg

    This movement does not have a quick-set function, but an interesting feature is the ability to turn the date backwards. As you can see, the date driving wheel has 2 fingers, one for advancing the date forward, one for backwards. To advance the date forward, one moves the date past twelve and then back to around 7, and repeats this process. Turning backwards until around 4-5 PM moves the date back.

    Removing the date-retaining plate, allows one to see the dial side of the movement. There is no fine finishing or polishing of screws on this side, but all the components are very solid and functionally well-finished.

    A nice detail are the 3 highly polished inserts that allow the calendar wheel to slide smoothly over the mainplate.

    20190827_183610.jpg

    In this movement design there is no traditional friction cannon pinion that holds the minute hand. Instead, the great wheel has an additional friction fit wheel that allows the hands to be set without damage to the geartrain. The steel wheel seen on the dial side is part of the great wheel, and it also drives the minute wheel. The minute wheel drives both the hour wheel and and the cannon pinion that holds the minute hand.

    The minute wheel is pressed against the hour wheel and cannon pinion by a wire spring to remove backlash. Without this additional spring tension, the minute hand might judder. I hope this explanation is somewhat clear.

    20190902_180817.jpg

    Moving on to the movement side, I have to admit I forgot to take pictures during this process. Anyway, it is a simple but extremely solid construction including the automatic winding mechanism. If there is anything of note I would say it is the use of 2 vertically-stacked wheels that look like winding pinions. These two wheels have Breguet teeth and are used to uncouple the manual mechanism when the watch is wound automatically. This mechanism should make the automatic winding mechanism more efficient.

    clean2 copy.jpg clean3.jpg

    The above pictures are after cleaning and oiling but before the assembly of the oscillating weight. It was not necessary to do any adjustment to the flat hairspring. Without doing anything I got a delta of 11 seconds on the timing machine. As the oscillating weight obscures the movement view I decided to only assemble it after casing. The oscillating weight itself holds a click that winds the movement in one direction only (anti-clockwise). It’s a very simple but seemingly effective mechanism. I'll have to wear it to find out.

    Finally, the watch was fitted with a new gasket.

    I don't know the history of this particular watch, but I was very surprised by how little wear I found in the movement. Even in all the winding components, there was barely any traces of wear or deformation. It leads me to believe that this watch may have been kept to be worn on special occasions only, or was somehow forgotten by its owner. Despite some marks on the caseback from opening by a "watchmaker", this watch has been very lucky to escape damage to the movement during its lifetime.
     
    Edited Sep 7, 2019
  2. Tony C.

    Tony C. Ωf Jury member Sep 7, 2019

    Posts
    4,502
    Likes
    11,319
    Nice breakdown, and a beautiful watch. I have long maintained that the cal. 133/133.8/71 are as fine or finer than any other bumper movements ever produced. JLC and Vacheron & Constantin also produced excellent bumpers, but I doubt that any surpassed the overall quality of the Zenith bumpers.

    It should come as no surprised that they were designed by Ephram Jobin, who was made famous by his fabulous cal. 135 chronometre movements.
     
    CaptainWinsor and Geezer like this.
  3. lindo

    lindo Sep 7, 2019

    Posts
    29
    Likes
    27
    Thanks for a very informative and beautifully illustrated examination of this extremely nice example: it is hard to imagine finding a better one. It will make me look more closely at Zeniths of this period.
     
  4. Geezer

    Geezer Sep 7, 2019

    Posts
    44
    Likes
    94
    Thanks! I fully agree that these movements are as fine as anything produced at that time. Throughout the movement there are many small details that could easily have been left out. For example the center seconds post that holds the seconds wheel is jewelled and can be easily replaced. Also many of the winding wheels have separate steel bearings that can be easily replaced if needed. It seems to be a movement made for longevity.

    Here it is clean and ready to wear.


    20190907_180855.jpg 20190907_180903.jpg 20190907_180915.jpg 20190907_180938.jpg 20190907_181005.jpg 20190907_181024.jpg
     
    Wetworks, Risto, KingCrouchy and 6 others like this.
  5. lindo

    lindo Sep 7, 2019

    Posts
    29
    Likes
    27
    Just the way I like a vintage watch. I would buy it in a heartbeat.
     
  6. pnwyankee

    pnwyankee Sep 7, 2019

    Posts
    215
    Likes
    231
    A great find and a top notch thread.
    Thank you
     
  7. STANDY

    STANDY schizophrenic pizza orderer and watch collector Sep 7, 2019

    Posts
    10,126
    Likes
    22,493
    Rose gold Captain I have
    Only 22 serial numbers apart

    image.jpeg image.jpeg image.jpeg
     
  8. pnwyankee

    pnwyankee Sep 7, 2019

    Posts
    215
    Likes
    231
    Lovely!
     
  9. Geezer

    Geezer Sep 7, 2019

    Posts
    44
    Likes
    94
    That's excellent! Fantastic watch and great to see such a close relative.
     
  10. CaptainWinsor

    CaptainWinsor Sep 7, 2019

    Posts
    887
    Likes
    1,555
    Has anyone ever determined what that symbol is on the back?
     
  11. Tony C.

    Tony C. Ωf Jury member Sep 7, 2019

    Posts
    4,502
    Likes
    11,319
    A Captain's wheel and Z for Zenith, no?
     
    STANDY likes this.
  12. CaptainWinsor

    CaptainWinsor Sep 7, 2019

    Posts
    887
    Likes
    1,555
    Works for me.