Omega Seamaster Diver 300

ErichKeane

IF you have the old one handy, when replacing them I measure the overall length of crown + stem, so I can closely reproduce THAT length (as that is more or less the important length). If not, trial and error is your only real bet.

Archer

Yes, that is the goal to make it the same as a set, but how you get there is the possibly tricky part.

Note that sometimes there is enough variation in the depth of the threads in the crown to cause an existing stem to be too short when the new crown is installed. So if you use the old parts as a guide, and cut the stem the same length as the original, you can get burned. I would leave some extra and sneak up on it.

This reminds me of school - we all left for lunch one day and when we came back all the stems on all our watches were broken. We were told we had 10 minutes max. to fit a replacement and we only had one new stem to use. Several people put the 2 halves of the old stem on the bench and used that as the guide to cut the new stem - I mounted the stem in the watch and cut it based on the case, trimming it down to the right length.

What some others didn't catch is that when the instructor cut the stems, he cut out a small piece on each one, so the people who used the old parts as a guide all failed - their stems were too short. It was an effective lesson for them...🤣

ErichKeane

I don't have experience with this watch, but typically the 'pop-out' is a feature of the crown itself. The spring is inside of it, not inside the movement. Can you compress/see it pop out as-is? I wouldn't expect the stem length to matter for that (unless it is slightly too long? What does it look like when you've tried to screw it down all the way?).

@redpcar has already edited his post, but your stem base has no problems. Stem for th at movement seems should look like this. NEW to me to see one without the little protrusion!