Probably from the late 1930s or early 1940s dates this small 8 3/4 ligne movement from Tavannes.
The Cyma 3 was also used by Alpina under their own caliber number “Alpina 755”.
The golden color gives this movement a high quality impression, and as you can see on the base plate, this is true.
With 15 jewels, it has got the common and technical minimum required equipment.
Of course, the gear train follows the classical standard with directly driven center minute wheel, third wheel, seconds wheel at 6 o’clock (here not prolonges axle for a decentral seconds indication) and finally the steel escape wheel, which has got relatively short teeth.
As escapement, a swiss pallet lever escapement was used.
The Guillaume screw balance (slotted bimetal balance), which is of course not shock protected, was upper standard that time, since it was able to compensate the temperature deviation of the hairspring.
The effective length of this haiespring was adjusted with a long regulator arm to reach the beating rate of 18000 A/h as precise, as possible.
Since the escape wheel is beared under its own cock, and the seconds and third wheel also have another cock, this movement is very service-friendly.
Another service-friendly detail is the click spring, which is inserted into the mainspring barrel bridge, and which is additionally secured with a recessed screw.
On the dial side, you can see the yoke winding system with its strong setting lever spring.
In the lab
Timegrapher resultYou clearly see the age of the movement. The amplitudes are not too high and the positional errors are quite high. Nevertheless, for a movement of this size, they are still not too bad.
|dial up||+25 s/d||252°||0.4ms|
|dial down||+14 s/d||274°||0.8ms|
|crown right (12 up)||-12 s/d||230°||0.6ms|
|crown up (3 up)||+95 s/d||215°||1.1ms|
|crown left (6 up)||+19 s/d||216°||1.0ms|
|crown down (9 up)||-110 s/d||239°||0.5ms|
|Size:||8 3/4''' (measured: 19,0mm)|
|Number of jewels:||15|
Guillaume screw balance (two legs)|
|Adjust mechanism:||Long regulator arm|
|Construction type:||solid construction|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||3 hole(s)|
Flume: 1947 21
Jacob: 1942 9 11016