Hello, A good friend gave me his father's Seamaster. The crystal is yellowed and I'd like to find a new one. The crystal measures a hair under 30mm on the outside. I took the case back off and it reads "Patent # 315.164" Under that's 2846 2848 and under that it has a big 3 followed by a small 3C. Without taking the watch apart and popping the crystal out, can anyone help with the correct size crystal I will need?. Otherwise, it keeps pretty good time knowing it hasn't has a service in probably 40 years and has been sitting in a drawer all that time. I took an early 60's Omega Constellation to my local watchmaker and he charged me $160 for just the crystal (says he got it directly from Omega). I thought that was a little much so I thought I'd try to find a less expensive crystal this time before I give him the watch to be serviced. Thanks for any help.
Which numbers on the case back are significant? How do I decipher the numbers. I know what all the numbers on the back of a vintage Seiko mean but I'm un-educated what the numbers mean on an Omega. Which is the case number, etc?
2846 and 2848 are the reference or model numbers, in this case there are two numbers meaning there were two distinct models using the same case. Ref 2848 used the caliber 490/491 sub-seconds movement and ref 2846 used the caliber 500/501 center seconds movement.
Thanks, I'd like to learn what all the numbers mean. Is there source material on how to understand Omega numbers? Thanks John