Hi all! Great to be a this wonderful place of watch enthisiasts! I'm trying to understand in detail the waterproofness concept of the screw-down crown from the 60-70ies as found on many Seamaster models, e.g. 166.088 or 166.024. (Part number 069ST42062). This is what I'm talking about: Of course I could tear down this one to see myself... eehm well better not. So, how many o-rings does the crown have? Are these even o-rings? Do the o-rings go around the shaft of the tube or at the end face or both? Here's a sketch to visualise my thoughts. I hope there's an expert on the forum who can guide me in the right direction! Thanks a lot & a great day to you all! J
A bit off the topic but a starter for 10,,, https://omegaforums.net/threads/omega-seamaster-600-ploprof-technical-guide.123328/
As noted above, several systems have been employed over the years, but I don't think that the Proprof or the naiad crown system are the most typical designs you will find on a vintage Omega. If you look inside a crown, you will see that there is typically a seal (o-ring) that fits around the tube, and this is true for both screw-down and non-screw-down crowns. One benefit of the screw-down crown is that it can't be rotated accidentally while underwater, which eliminates one source of water intrusion.
Thank you all very much for the input! Indeed I have seen a few of the links before, but never found something specific about that typical 60ies Seamaster screw-down crown… I guess it probably is as @Dan S is proposing: o-ring that goes around the tube. One question is still, if the o-ring is squeezed in some way when screwed down. And if yes, then how exactly. Maybe we will still find the answer!
Thanks @Omegafanman for the Ploprof link. This one seems to have two o-rings, and the smaller one supposedly goes on the step and squeezes in there. While the larger one goes around the the diameter.