Between 1955 and 1963, the east german VEB Uhren und Maschinenfabrik Ruhla produced the 15 jewels caliber UMF 39-80, also known as "UMF M 3D", which belonged to the "Diva" caliber family.
This version of the 8 3/4 ligne movement had no shock protection.
Unlike the direct relative UMF 39-50, the caliber 39-80 no longer reveals its former pin lever construction and the base place now reminds of a true pallet lever movement.
All important bearings are now equipped with rubies and the cutouts for the escape wheel are much smaller now, there are only two holes for oiling the lever pallets from the dial side.
The gear train is the traditional construction with directly driven center minute wheel, third wheel, seconds wheel a 6 o'clock and escape wheel.
The UMF 39-80 is in fact a pillar construction, but the use of a massive housing around the gear train, this is hidden very well. Only the balance cock, which sits on top of two pillars, relevals it.
The screw-less anular balance, which beats with the traditional 18000 A/h is not shock protected and regulates a swiss type pallet lever movement.
On the dial side, you see the rocking bar winding system and the well made ratchet.
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