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  1. dstern Jul 10, 2017

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    I have a 168.005 Cal. 561 at the watchmaker for service. As he was completing service, the rotor was rubbing the caseback. When I asked about the cause, in particular about whether the rotor pivot was loose, he answered with this explanation: "he case-back seems to thread a little deeper into the case-middle about .20 of a millimeter not allowing for proper clearance of the oscillating weight when case back is sufficiently torqued down. The correction was to use a larger O-ring gasket allowing the oscillating weight more clearance." Does that make sense as a diagnosis, and is the "fix" an acceptable one? I'd appreciate your thoughts.
     
  2. Larry S Color Commentator for the Hyperbole. Jul 10, 2017

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    Not a watchmaker. If this was my watchmaker my BS alarm would be going off. i don't think I'd accept this.
     
  3. JimInOz Melbourne Australia Jul 10, 2017

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    maxwell-smart.gif
     
  4. ATracyWatches Jul 10, 2017

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    Thr most likely explanation would be that the axle for the oscillating weight is worn and therefore causing excessive play on the oscillating weight. This is the most likely cause of the running on the case back.
     
  5. JimInOz Melbourne Australia Jul 10, 2017

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    :thumbsup:
     
    lando and Larry S like this.
  6. Temprus Jul 10, 2017

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    +1
     
  7. Temprus Jul 10, 2017

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    Technically this "fix" is not acceptable. If there is no issue between axle and oscillating weight, your watchmaker can be right!
    Probably the watch case isn't made by Omega factory and for this reason the case back thread deeper than it should. Or the dial model originaly doesn't belong to the case. Or it have a wrong chrystal and his ring, which pushes the dial down.
     
  8. Kwijibo Jul 11, 2017

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    I don't undesrtand.The rotor touches the caseback or the edges of the movement?
     
  9. Larry S Color Commentator for the Hyperbole. Jul 11, 2017

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    Case back. Seems common issue with 561.
     
  10. dstern Jul 11, 2017

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    Thanks for the responses. It is clear that I should have provided more information. The case and caseback are original, a Ref. 168.005, driven by a Cal 561, bought from an OF private seller. The rotor was rubbing the caseback but not the bottom plate. When asked about the cause, and explicitly about whether the rotor pivot was worn, he responded with the explanation I began with, that the caseback screwed too far in by .2 mm so that the rotor rubbed, and the fix was to install a larger gasket. My questions were 1) whether this diagnosis is credible and 2) whether the fix is appropriate. Thanks.
     
  11. Archer Omega Qualified Watchmaker Jul 11, 2017

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    The axle doesn't wear that much - it's steel. The brass pinion (that has the bushing) is what wears the most since it's much softer.

    The rotor rubbing the case back can have a few causes - one is the wear mentioned, so the solution there is to replace and ream out the pinion to reduce the play.

    The next thing I would look at is if the rotor has been bent - I see a lot of these where "watchmakers" don't replace the worn pinion, and just bend the rotor up so it doesn't scrape the plates.

    If both of the above things are okay, I would check to make sure it has a correct Omega crystal with a proper stepped tension ring. If it doesn't this could push the movement further back into the case causing interference between the case back and rotor. The correct solution to this is not a thicker gasket. ::facepalm2:: Clearly using a genuine crystal is the right solution.

    The bottom line is that if all the parts are original and in good shape, there is no need to fit an improperly sized case back gasket to the watch. The watchmaker needs to look at all these things, find the problem and fix it properly, rather than masking it with an incorrect part.

    Cheers, Al
     
  12. Kwijibo Jul 11, 2017

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    well, if the rotor does not touch the plate, it must not be the axis that is damaged or bent. The casebacks are usually very close to the movement so he may be right. screw down case back isn't it?
    what is intreaguing is that Omega usually don't have natural flaws like touching the rotor when fully screwed in caseback.
     
    Edited Jul 11, 2017
  13. Archer Omega Qualified Watchmaker Jul 11, 2017

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    No...
     
  14. Kwijibo Jul 11, 2017

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    Hi Archer,

    Porbably not that close you're right. do you often see some bent rotors? One thing i did not think about, when you hear some noise in your movement sometine the casing screws are lose and in contact with the edge of the rotor.
     
  15. Archer Omega Qualified Watchmaker Jul 11, 2017

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    From my post above...

    "The next thing I would look at is if the rotor has been bent - I see a lot of these where "watchmakers" don't replace the worn pinion, and just bend the rotor up so it doesn't scrape the plates."
     
  16. Kwijibo Jul 11, 2017

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    sorry, I red too quickly, I rarely saw some.
     
  17. ChrisN Jul 11, 2017

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    Out of interest, I have a 168.005 open at the moment and can take a picture to show what Al is saying about the crystal tension ring. Here it is and I've indicated the profile in green. You're looking from the back inside the case.
    168005.jpg

    The step down in this Omega crystal looks about 0.30-0.40 mm so, it lets the movement come that much further forward than if it was a generic without the step. Does your crystal have the Omega symbol?

    Still, as Al says, I bet it's the bush. Did you get this information from your Watchmaker or the seller? It's not clear to me.

    Regards, Chris
     
  18. dstern Jul 11, 2017

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    Thanks, Al. I was hoping that you would respond to my query. I am pursuing this with the watchmakeer, who is the source of the info.
     
  19. Archer Omega Qualified Watchmaker Jul 11, 2017

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    Stepped tension ring in cross section...

    [​IMG]

    Cheers, Al
     
  20. dstern Jul 11, 2017

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    Thank you, Chris. The crystal is Omega signed, but I'm asking him to confirm that it is the correct one and has the correct tension ring too, as the service history of this watch is not known.