Screw down crown gap after servicing

Once the repair is finished and the new crown screwed onto the case tube (without the movement in the case), a mental note should be taken as to how close the crown is to the case when tightened on the tube. The aim should be to have the same amount of gap once the movement is fitted into the case, and the crown and stem fitted. If the distance is the same before and after the movement is fitted, you should be okay.

Looks goofy to me. Is there some reason you don't want to ask the watchmaker about it?

Simple! Ask him to test how close the crown screws on with the movement OUT of the case. It should be the same with the movement IN the case as it is with the movement OUT of the case He might have to shorten the stem a bit. The key here is that the crown must screw on far enough that it “bottoms out’ when it tightens against the outer end of the tube.

Just FYI the idea that new seals will cause the crown to stick out from the case is not really true. There is only one seal at work here, and it goes over the case tube, so being new or not has no affect at all on how far the crown screws down. The only time this would be an issue is if there was a seal inside the crown that butts up on the face of the case tube - Rolex does this on some models, but not Omega (at least not that I can recall off the top of my head).

For the 25318000 there were 3 different cases used on this model over it's lifespan. Do you know what the case number is for your watch? It appears to be an early one but knowing the number would tell me for sure which crown goes on the watch. The early versions used crown 069ST42123 rather than the later version 069ST42147. The 42123 is a shorter crown than the 42147. So although it's probably the stem not being cut to the right length, there is a chance that the wrong crown was fitted and it may not fully screw down onto the case tube.

Cheers, Al