Calibre 321 Service Dials

Omega supplies service dials for a 321 speedmaster, which is pretty unusual service for a company to continue to supply parts for an item manufactured at least 45 years ago. This modern dial is easily spotted as it has Superluminova Markings. A simple lume test will show it. (Expose to strong light for a few minutes, then switch off and observe – a strong glow indicates Superluminova)

Modern Omega Service Dials, for Calibre 321. The dial on the left has a double print of SWISS MADE
Modern Omega Service Dials, for Calibre 321. The dial on the left has a double print of SWISS MADE. These dials would be the same as the ones fitted by Omega when they service a 321 Speedmaster at Bienne today. When fitted to a watch, a collector will reduce the value to that of the remaining parts combined.

It would appear Omega has manufactured a variety of “Service Dials” for 321’s that were used throughout the 1960’s and later. These pre c1994 (my estimated date) dials are not the same as the 321 service dial available today.

Here are some examples of Calibre 321 Speedmasters with Omega made, service dials. These dials vary from original specification but are clearly Omega made, and made for the Calibre 321. When fitted these earlier dials still reduce the overall value of the piece, but not as much as superluminova’s.

321 service dials
Each of these watches carries a early service dial, with characteristic combinations not seen in the original specifications. All carry the correct feet for a 321 speedmaster. None of these examples have an applied metal logos. Note the length of the hour indices on the dial, and the T markings, or lack of them, and the spacings.

They can easily be spotted as they are tritium, some with T marks of wide spacing, some of narrow (similar to early 105.012’s) and with painted logo dials instead of applied metal logos.

I believe the dials pictured above with no T marks are still Tritium, as they do not glow comparably with the superluminova. I cannot explain this.

Since writing this, I have come across several short indices, AML dials with 321 feet. Here are some examples:

145.012-67 from Ebay. Note the short hour dial indices and Applied Metal Logo, along with T marks. The step is shallow

Here is another example of a service dial owned by a member of

Service Dial: AML, Short indices, and T marks. This dial is very shallow, almost flat. However not as flat as a MkII dial.



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