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Mlgboy

Oris Big Crown sub seconds pinion

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Hi Guys, 

Hoping for some help sourcing a part for an Oris Big Crown which I am in the middle of servicing. The watch movement is essentially an ETA 2836-2 which had sustained damage to most of the keyless works especially the ratchet wheel which ended up with very few teeth left on it. Not sure how this had happened but the owner had noticed some slipage when winding but not the accumulation of debris inside the display back. Needles to say the movement was heavily contaminated with material from the ratchet wheel. Following a complete strip, clean, rebuild, lubrication and a number of new parts its now back to working and running well. Only problem is the movement has a sub seconds dial at the 9 o'clock position but the pinion, which is driven by the third wheel is damaged. I have done the usual search with my goto supplier for parts, Cousins, but cannot track down a replacement pinion or even find any reference to it on the net. Any help would be most gratefully received.

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If it's an ETA 2836-2 based ORIS movement then as far as I can ascertain this will apply to either the calibre 644 or 690. [I suspect the former as the latter seems to have an additional complication for a second time zone as a further sub dial which you do not mention].

Like you however I've drawn a blank finding out any information / parts for this calibre . :(   The reason I'm replying is in case, if you agree with the above, another forum member has any further knowledge on the calibre.

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4 hours ago, WatchMaker said:

If it's an ETA 2836-2 based ORIS movement then as far as I can ascertain this will apply to either the calibre 644 or 690. [I suspect the former as the latter seems to have an additional complication for a second time zone as a further sub dial which you do not mention].

Like you however I've drawn a blank finding out any information / parts for this calibre . :(   The reason I'm replying is in case, if you agree with the above, another forum member has any further knowledge on the calibre.

I can’t confirm the calibre as the only numbers on the movement are the ETA ones but sounds the same to me.

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I did look at the 645 for you when investigating but discounted it as the parts sheet (available via Cousins) only details a sweep second. :unsure:

I hope you get a break on this; it's no fun hitting a wall on an elusive part.

Almost certainly a dead end so I'm not sure why I'm suggesting it but ... perhaps look at other ETA movements that do have an obvious small / sub seconds part (e.g. 2895-2) and compare to your broken part for a possible fit.

As a last resort you might have to fix the pinion on your broken part. 

Good luck!

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