Hello,

I recently purchased an Omega Chronostop Genève from eBay. Home work was done and the exterior of the watch looks good, however there was no pics of the movement.

I was thinking on opening the case back to ensure the cal is 865. Are the friction balls effective and once the case back is open are there any precautions to take when screwing it back on.

I have never attempted to remove a case back.

Thank you,

 

It might work and it might not. If the gasket has turned to glue then it won’t be enough, but if it’s been serviced at some point then it may spin off pretty easily. With a ball you can’t hurt it by trying. It’ll be an 865 (or 920 if it has a date wheel). I can’t think of any other movement that does what the CS does.

Do it in a clean dry place and when putting it back ensure it engages with the threads correctly. Don’t trust it to be remotely water resistant after it has been removed. Remember to record or photograph the serial while you are in there.

 

I have one and love it. If it doesn’t work then I take the watch to my watchmaker because I don’t want to damage the case with the other tools. Most of them are cheap chinese stuff and I have found they tend to slip on the back. Don’t want to take the chance.

 

Friction balls will often fail at opening case backs that have been in place for a long time or have melted gaskets. For opening backs first time after arrival, I favour using superglue and a socket wrench and then replacing the gasket.

 

Depends on how brave I'm feeling and how much I like the watch

My normal MO is:
* friction ball (as it's easy to hand and doesn't need adjusting) - then if that doesn't shift...
* @Pahawi case back opener if it's a Speedmaster, or a smaller watch (I have 2 sizes - I think the 2nd one is intended for Constellations, but it's also the perfect size for Seiko 6139s. Trouble is, I used it on a watch that was stuck so tight, it actually blunted the brass teeth of the opener... ... or else...
* careful use of 3-pronged adjustable case back opener (using a vice, a case holder, and setting the thing up while wearing a loupe so I can see that it's correctly sized) and if that doesn't shift it and the brave pills kick in...
* The superglue/socket method is depicted and described here if you've not seen it previously...
http://www.vintagewatchadvisors.com/2019/07/06/how-to-remove-the-stuck-back-of-a-watch/

 

I had a really stuck case open after hours of trying with the ball.

 

1) no substitute for a proper case tool.
2) it can only be an 865 if everything works and there is no date change detent in the crown settings. There are no other movement possibilities and not really anything close for fakers to use.

 

Thank you everyone for the comments, very helpful. I think I will start with a ball and eventually purchase a real tool to remove case backs.

Reassuring to know only the 865 is going to fit. I will post pics when it arrives.

Thanks again,

 

Never had much luck with a friction ball.

 

A 920 movement (same as 865, but with a date function) will also "fit" - but again, you will know when you check if there is a "date detent" setting on the crown. VERY unlikely someone put a rarer 920 movement into a 145.009 or 145.010 case.

What is more likely is that it's an 865 movement in a 145.009 case that will need a complete service when you receive it. As a chronograph movement the service isn't going to be inexpensive.

 

Bought one ... miserable failure. I have a Kong lying around somewhere, heard they work better. Have not tried it yet.

 

This set up worked for me one day in a pinch. Find a suction cup that is slightly larger than the case back. Remove the wire hook, and use a short ratchet, shallow socket, and great care.
I would suggest taking it to a watchmaker if this, or Con’s superglue/socket method doesn’t work. Good luck and be cautious!!
Tom

 

One thing with the ball - keep I inflated. If it's deflated too much, then when you compress it against the case back, it will also contact the lugs of the case, and this will make it difficult to get a case open with it.

 

Here she is, everything appears correct. The brushing looks factory, no polishing (only the polywatch I applied), the crystal is signed and the strap appears to be original.