UMF 83-31 (M 1)

 
UMF 83-31 (M 1)

UMF 83-31 (M 1)

Description

Already in 1923 Thiel released their 18 ligne pocket watch movement, called “Regular”. It was a simple, but in details clever constructed pin lever movement.

During its 67 years of production, the name changed several times, from Thiel Regular to UMF Regular, to UMF M 1 and finally to its ultimative name, UMF 83-31.

UMF 83-31 (penultimate model F3)

UMF 83-31 (penultimate model F3)

Not only the caliber name changed over time, but also the execution, where at the end not only the separate balance cock vanished, but also the lever cock. And in the last version, called F4, the hour wheel became a plastic part.

base plate

base plate

On the punched base plate, which is brass toned in the older versions till the early 1970ies, you can immideatly see, that it is a simple pillar construction, on which the gear bridge sits on three pillars. Of course, there are no bearing jewels.

gear train

gear train

The gear train could not be more classical, no wonder, since it originates from the 1920ies: The mainspring barrel (which could be released seperately) drives the center minute wheel, followed by third and fourth weel on which the decentral seconds hand sits. Finally, there’s the escapement wheel.

side view of the gear train

side view of the gear train

There’s a little speciality on the lever - probably to increase its operational safety, on its gear side end, there’s an u-shaped form, which sits above the escapement wheel and on extraordinary deflection, it should bump into the axle of the escapement wheel and would so prevent bending the lever pins.

Pin lever

Pin lever

The UMF M1 (83-31) of course has got only a simple screw less anular balance, which runs in two punch bearings, of which the one on the dial side is adjustable in its height. Since this is a very rugged construction, there’s no other shock protections.

UMF 83-31 (Model F3): Dial side

UMF 83-31 (Model F3): Dial side

Surprisingly, a real ratchet with a true pawl was used and not only a simple click spring. Besides this, this movement has got the expectable rocking bar winding mechanism and large holes for the escapement wheels and the lever, which allows easy service.

At 3 o’clock you see the height-adjustable balance wheel bearing.

Technical data

Manufacturer:UMF
Caliber:83-31
Escapement:Pin lever
Balance types: Nickel anular balance
Shock protection(s): none
Balance bearing / direction hairspring:Clockwise
Moveable stud:no
Adjust mechanism:Hairspring key
Construction:
  • lever
  • escape wheel, seconds wheel, third wheel, center minute wheel, mainspring barrel
Construction type:pillar construction
Winding mechanism:rocking bar winding system
Setting lever spring:2 hole(s)
Functions:hour, minute, decentral second
A/h:18000
Size:18''' (measured: 38,7 / 44,2mm)
Production period:1923 - 1990
Literature: Flume: 1947 92
Inventory number:17027

Usage gallery

UMF Regular pocket watch

UMF Regular pocket watch

Ruhla pocket watch  (parts only)

Ruhla pocket watch (parts only)

This movement in two versions including pocket watches is a donation from Mario to the movement archive. Thank you very much for your great support!