If you think of ETA, you think of all those modern selfwinding movements, which ETA produced after WW II, and which still power most of the mechanical watches in the upper price range on the market.
It's less known, that the ETA also produced many cylinder movements in their early days, but not many of them survived until today. Watches with cylinder movements were found in the lower price range and due to their lack of precision and reliability they were not really loved.
The ETA 415 shown here probably originates from the 1930ies. It is a rather small cylinder movement, elliptically shaped for the popular Art Deco watches of that era.
Interestingly, on this movement, the plates are made of nickel silver and not of brass, as on most other cylinder movements. This gives the movement a much more modern touch.
The gear train is the usual one for a cylinder movement: The mainspring barrel drives the minute wheel, then we have got fourth and third wheel and finally the inidividually beared cylinder wheel. All gears are ruby beared, the cylinder wheel has got its own flat cock, because it lies under the balance wheel.
The three-leg, flat anular balance with its cylinder tampon is not yet shock protected. It beats with 18000 A/h and is located in its own balance block, which can be removed from the movement:
On the dial side, you see, that the ETA 415 already uses a modern yoke winding system.
At 6 o'clock you can spot the old ETA hallmark, which was used unil the end of the 1930ies.
In the lab
The specimen shown here was lacking a few parts of the winding and time setting mechanism, and since it's a cylinder movement, it could not be measured on a modern timegrapher.