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  1. sat968

    sat968 Dec 1, 2017

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    Following a conversation I had with @JohnSteed, I started looking at chronometer calibers. Looking at a caliber from a watch in the recommended eBay thread,

    chro.jpg

    it looks like the rotor has been changed sometime during the life of the watch since it is a different color from the movement parts. When this happens, is the only recourse available to a buyer to check the integrity of the watch the integrity of the dial? I.e., if it looks like a redial and it's obvious that the rotor or bridge with the chronometer engraving has been changed, it's a double warning.

    I'm just curious if there is something else to check, or if we're deep into the eBay wild west and caveat emptor. I guess that is why others are recommending specific eBay sellers. I guess the takeaway is caveat noob like me...
     
    IDXM likes this.
  2. gatorcpa

    gatorcpa ΩF InvestiGator Staff Member Dec 1, 2017

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    With these cal. 50X movements, the rotor bearings are weak links. It was common for watchmakers to replace the entire rotor assembly, rather than just the bearings, as that is how Omega sold the parts.

    On the other hand, this could just be a Mumbai Special frankenwatch. There is no way to tell from information provided.
    gatorcpa
     
  3. X350 XJR

    X350 XJR Vintage Omega Aficionado Dec 1, 2017

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  4. sat968

    sat968 Dec 1, 2017

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    There was also a watch in the private sales section that had a chronometer on the dial, but nothing in the movement. I think I may have mixed up my images. IMG_2366.JPG
     
  5. gatorcpa

    gatorcpa ΩF InvestiGator Staff Member Dec 1, 2017

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    I’m so confused. ::confused2::
    gatorcpa
     
  6. sat968

    sat968 Dec 1, 2017

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    Sorry about that. My fault.

    In the last image, the dial indicated it was a chronometer. The movement had the rotor replaced and the engraving on the movement should have been on the rotor or bridge, which is missing in this photo.

    So the question is, is there another way to tell if a movement is chronometer rated other than the engraving?I can see a couple of things happening.

    1) A watch goes in for service and the rotor/bridge is replaced with the version from the base, non-chronometer movement. Now you can't easily see that the movement is a chronometer.

    2) A bad actor swaps out the rotor/bridge to make the movement look as if it's a chronometer.

    For this watch in question, I'm guessing it was just a bad redial causing the mismatch, but I wanted to understand this on a deeper level, if said deeper level even exists...
     
  7. gatorcpa

    gatorcpa ΩF InvestiGator Staff Member Dec 1, 2017

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    Cal. 504 is a 24 jewel movement. The base movement for this series, Cal. 501 is either 19 or 20 jewels. So theoretically, there should be a way. Unfortunately, you’d need to take the entire movement apart to make that determination.

    Cal. 752 is not a chronometer rated movement, so that one is either a put-together movement, or an incorrect replacement.

    Some earlier Omega chronometer movements (i.e. cal. 352) had special regulators and/or mirrored finishes on the ratchet wheels.

    Hope this helps,
    gatorcpa
     
  8. sat968

    sat968 Dec 1, 2017

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    sure does. Thanks.
     
  9. Deafboy

    Deafboy His Holiness Puer Surdus Dec 1, 2017

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    BTW, though a bit off topic here, I would like to point out that the term chronometer for a Swiss watch means that the watch was adjusted and tested to meet chronometer specifications. It is meaningless to describe a watch as chronometer rated 50 years after it was certified. It would need to be re-certified, and most likely need a competent watchmaker to service it (dismantled, cleaned, reassembled, replace worn parts, lubricated, and also do the labor intensive adjustments to meet isochronism and positional variances required for the timepiece to meet high accuracy specifications). A 50 year old mechanical watch, whatever specifications it met 50 years ago, will be way off chronometer standards unless recently serviced.
     
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  10. Archer

    Archer Omega Qualified Watchmaker Dec 2, 2017

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    Taking this one step further, Omega does not consider any of these old movements to be chronometers anymore. The timing specs on all of these only require checking to 3 positions and not 5, and the tolerances for Delta and average rates are no different than the non-chronometer versions.
     
    Deafboy likes this.