Hi A few months ago I found a vintage crown to replace the service crown on my 1967 SM300, although I now think it may be a Speedmaster crown? its 6.8 mm dia. 3.8 mm deep without the brass tube bit & 24 teeth (measured to only 1/10th mm accuracy) I have found a trade with this crown 6.7 mm dia. 3.35 mm deep, 24 tooth Can anyone help with what's right as I believe there might also be some later Railamaster flat-foot crowns with the same dimensions, and what would be an appropriate value for the Seamaster crown trading against the possible early Speedmaster crown Thanks in advance Regards Mr.H
Have a look at this post https://omegaforums.net/threads/new-member-ed-white-crown-question.60131/#post-748493
Hi Thanks for that Gemini4 said ""remember the the 24 point flat foot crowns came in at least 3 flavors: 1.0mm stem = 321 movement for Speedmaster 1.2mm stem = 284, 285, 286 movement for 2914, 135.004 Railmaster 0.9mm stem = 501, 552, 565 movement for 2913.14755.165.X, 166.X Seamasters Luckily, watchmakers can adapt an incorrect stem size."" td69 said ""Aside from having the different stem sizes, the height of the crown is varied as well. The correct A1 flat foot crown for 321 Speedmaster should be 3.8mm in height or thickness however you call it compared to 3.0mm for some of that of 2913/2914 on Railmaster and Seamaster, while sharing the same 6.75mm in diameter."" As close as I can measure it the total height of my current crown is 4.8 mm so the brass tube part attached to the crown is 1 mm tall & 1.4 mm o/d, the stem is 0.9 mm, although I am unsure if it has been adapted .. I must admit (if there are some Seamaster crowns the same depth as Speedmaster) I cannot work out what crown I already have ..... & at 3.35 mm deep what the swap crown is actually for? Can any one tell me if I'm right in thinking no Seamaster 165.024 non screw-down crowns have the extended brass tube part? and the depth of a Seamaster 552 crown with a 0.9 mm stem should be around 3.35 mm Regards Mr.H
Hi, The crown you have is a Speedmaster flat foot crown. The other one looks like a Seamaster 300 Naïad crown, 6,8X3,35 mm are right and I beleive the tube is short. Now you can only suppose it is the right one, you will eventually know when you try on your SM 300. Good luck.
+1 for the flat foot Speedmaster crown you have, but I don't know whether it will ever correctly fit your 165.024 Seamaster. I went through some Google images of 165.024 and don't really see this crown fit in, hence no extended brass tube part will fit it. Perhaps some OF members knowledgeable in Seamaster will chime in.
Found a photo of two crowns. The left one is an A1 flat foot 24-tooth Speedmaster crown with a little tube protruding from its height, and the right one is what I believe a vintage flat foot crown for the early Railmaster CK 2914 & Seamaster CK 2913. 3.8mm vs 3.0mm in thickness.