One of the more seldom to find movements is the form movement ETA 1150, a contemporary, rather flat windup movement with a size of 5 1/4 x 8 3/4 lignes, perfectly suited for the tiny rectangular ladies’ watches, whose size was liked to hide to let them appear more elegantly.
The 15 jewels it uses, is the standard of a good quality pallet lever movement, and below the pretty large screw balance there’s also a perleage.
Due to its small size, which allows a rather large mainspring barrel and balance, though, the gears are pretty small, especially the really tiny seconds wheel.
To save space, the lower bearing of the seconds wheel is located in half height, below, there’s place for the normally sized escape wheel.
The two leg screw balance is not yet shock protected. Its slow beating rate of 18000 A/h can only be adjusted with the hairspring key, since there’s no long regulator arm.
On the dial side, you can see besides the yoke winding system with its very characteristic
setting lever spring, how there was a fight for every 1/10 of a millimeter of height:
On top and and the bottom, you can see how the base plate is slanted on the dial side, on the botton, the mainspring barrel is partially uncovererd and on top, the cap jewel bearing for the dial side balance wheel is partially cut.
|Number of jewels:||15|
Nickel screw balance|
|Balance bearing / direction hairspring:||Counterclockwise|
|Adjust mechanism:||Hairspring key|
|Construction type:||solid construction|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||2 hole(s)|
|Size:||5 1/4 x 8 3/4''' (measured: 13,0 x 19,6mm)|
Flume: K1 -|