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UMF 39-50


UMF 39-50UMF 39-50


The UMF caliber 39-50 is one of many versions of the 8 3/4 ligne midsize movement type, called "Darling". Here in subversion 50, it only displays hour and minute, does not have a shock protection and contains only seven jewels.

Version with screw-less anular balanceVersion with screw-less anular balance

It was available with screw balance as well as with a screw-less anular balance.

base platebase plate

The "darling" caliber is a rather simple pillar construction, and when you look at the base plate, there's no indication, that it is at least a true pallet lever movement.

gear traingear train

The UMF 39-50 has got a traditional gear train with directly driven center minute wheel, followd by third wheel, fourth wheel at 6 o'clock and escapement wheel.

Seitenansicht des RäderwerksSeitenansicht des Räderwerks

Since it is a pillar construction, it builds pretty high.

The non shock protected anular- or screw balance beats slowly with 18000 A/h, but regulates a classical pallet lever movement of swiss type. With the four balance wheel bearing jewels, the elipse of the balance and and the two lever pallets, the UMF 39-50 reaches a total of 7 jewels.

Detail: Flitter spring on the mainspring barrelDetail: Flitter spring on the mainspring barrel

On top of the main spring barrel, on its axle, there's a so-called "flitter", a flat spring. No idea, what this is good for, and also no idea, why the mainspring barrel is rather flat.

dial side of the version with screw-less balancedial side of the version with screw-less balance

The movement itself is very lean constructed and service friendly. On the dial side, almost the whole escapement wheel can be seen, just as on skeletonized movements.

As usual for UMF, this movement has got a rocking bar winding mechanism.

UMF 39-50: Dial sideUMF 39-50: Dial side




 Technical data

Number of jewels7
EscapementAnchor with pallets
BalanceNickel screw balance,s
Shock protection(s)none
Balance cock directionclockwise
Hairspring studfixed
Regulator typeHairspring key
Movement constructionFork
Escapement wheel, Fourth wheel, Third wheel, Center wheel
Mainspring barrel
Construction typepillar construction
Winding mechanismRocking bar
Setting lever spring2 holes
FunctionsHour, minute
Beats per hour18000
Size83/4''' (measured: 19,8 mm)
Image in Flume Werksucher K3 17
Inventory ID 17044
UMF 39-50UMFUMF39-508 3/4'''UMF 39-507 Jewels, 8 3/4''', 18000 A/h




Usage gallery

unmarked ladies' watchunmarked ladies' watchUMF ladies' watch (still with old "5 jewels" dial)UMF ladies' watch (still with old "5 jewels" dial)




The movement with screw balance and the watch, it belongs to (which still has got the old "5 Jewels" dial) is a kind donation from Mario. Thank you very much for supporting the movement archive!