zOwie Omega Discussion Forum

: I have inherited a Omega watch and would very
: much like to find more information about it
: (Model, year, etc). I had a jeweler open the
: case (which appears to be 18k gold) for me
: and found the serial number 10158599 on the
: movement.

: Thanks in advance!

:

Several things:

Omega watches of this era had two serial numbers on gold watches.

The movement had a serial number, which can date the watch. Your movement could be from between 1944 and 1951, but most likely about 1945.

Movements manufactured January 1949 and after have a "calibre number", three digits beside a Greek letter Omega (looks like a horseshoe and is also on the watch's face). If the movement does not have a calibre number, it is from before 1949.

The other serial number is engraved in the interior case back and is similar in format but not the same number as the movement number, like 10xxxxxx. An Omega logo and a model number of 4 digits should also be engraved in the inside case back.

The mark on the exterior caseback is suspicious to me, as it is 18k/0.800. 18k gold is 0.750 and should be marked as such, and all factory issued 18k Omega cases had such marks.

If the movement is an Omega movement, it will look like one of these, the bumper automatics which occurred in several variations and two sizes 28.10 mm and 30.10 mm.

The only visible differences is the earliest models had springs exposed, later didn't and there were variations in the regulation method. The two sizes were basically indistinguishable.

I show two sizes of the older movements above, with the springs exposed and no calibre numbers.

Here are two later models with covered springs and calibre numbers.