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UMF 44

UMF 44UMF 44

Description

In 1938, the Gebrüder Thiel GmbH in Ruhla, Germany, launched the caliber "Start", a simple pin lever movement without jewels, which was made until the 1960ies. Its further development was the caliber "Chronos", starting in 1950, which contained an indirectly driven center second indication and was constructed from the beginning with a balance bridge.

The last, 8th, version, which was released 1959, got the official name "UMF 44" and was made until 1963. The specimen shown here was made in the 26th week of 1962. 

 

Construction

base platebase plate

The brass base plate is punched and little decorated with a dot pattern. The upper plate is beared on three pillars.

You can see the simple click mechanism, which consists only of one single piece, a punched click spring.

gears and trainsgears and trains

The construction of the UMF 44 is simple and clean: Mainspring (at "11:30"), directly driven center minute wheel, second wheel, third wheel and escapement wheel. The latter one is controled by a pin lever. The screwless ring balance, which is not shock protected is beared in two ruby-less pivot bearings under a bridge.

The indirectly driven center second hand is driven by a second gear on the second wheel.

side view of the gearsside view of the gears

As on all Ruhla pin lever movement, it builds very high, which makes it a bit difficult to put the escapement lever under its cock. The pro side of this construction is, that it is pretty rugged.

UMF 44 dial sideUMF 44 dial side

On the dial side, you see the height-adjustable pivot bearing at "9", and the rocking bar winding mechanism.

 Technical data

Manufacturer
Caliber
Factsheet

 

In the lab

The specimen shown here was completely gummed and got a full service. It was adjusted as far as possible, and even the hairspring needed a minor correction, but the enormous beat error was not resolved.

Timegrapher protocol

crown rightcrown right crown topcrown top crown leftcrown left crown bottomcrown bottom 
dial topdial top dial bottomdial bottom 

vertical positions
12 up  +30 seconds/day
3 up  -150 seconds/day
6 up  +35 seconds/day
9 up  +130 seconds/day
horizontal positions
dial down  +20 seconds/day
dial up  +25 seconds/day
timegrapher measurings
 

Due to the enormous beat error, it was very difficult to create readable diagrams on the timegrapher. But from that, what was measured, you can state, that for such an old and heavily used pin lever movement, the rates are pretty well, and worn, the daily deviation should not exceed one minute per day, which is probably even better than the original specifications of that movement.

Usage gallery

UMF Ruhla mens' watchUMF Ruhla mens' watch

Links