The Omega R13.5 dates from the 1940ies. It is a ladies' watch form movement, which got its alternative name, caliber 240, in 1949 and was made until the late 1950ies.
Of course, all important bearings have got jewels, self-evident for Omega.
The gear train is truely classic with a directly driven minute wheel, third, fourth and escapement wheel. The shape of the base plate allows a large mainspring barrel and also a large screw balance.
The large screw balance already beats with 21600 A/h, which was very modern for the time.
It is not shock protected and controls a swiss pallet lever movement.
On the dial side, you see the yoke winding system and the cap jewel of the balance wheel bearing. Besides the balance wheel bearing, no other bearing contains cap jewels.
In the lab
Timegrapher resultAs you can see, the balance is the problem here, a new balance wheel is neccessiary. But for occasionally wear, it is still sufficient, the rates are compensating themselves in all positions.
|dial up||+29 s/d||148°||2.7ms|
|dial down||-7 s/d||134°|
|crown right (12 up)||-270 s/d||125°|
|crown up (3 up)||+197 s/d||201°|
|crown left (6 up)||+115 s/d||131°|
|crown down (9 up)||-300 s/d||133°|
|Size:||6 x 7 3/4''' (measured: 13,4 x 17,5mm)|
|Number of jewels:||15|
|Balance bearing / direction hairspring:||Clockwise|
|Adjust mechanism:||Long regulator arm|
|Construction type:||solid construction|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||2 hole(s)|
Flume: 1952 -|