FHF 251

 
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FHF 251

Description

In the late 1940ies, FHF released a manual wind movement in a contemporarily modern construction with directly driven center second. This caliber 25 (and its twin FHF 28 had a diameter of 10 12 lignes.

The nomenclatur of FHF was in a way, that an additional “1” at the end marked the same movement, but with a larger base plate, and so, the FHF 25 was transformed into the FHF 251 described here with a diameter of 11 12 lignes.

base plate

base plate

The specimen shown here is in a red-gold tone, visually very nice!

On the base plate, you can see the larger diameter, whose additional outer area isn’t used.

minute wheel bridge

minute wheel bridge

As on most movements of that time, a two-storey construction is used, with a minute wheel, which is beared under an own bridge. The third wheel at 4 o’clock is connected to it and drives the central second wheel.

gear train

gear train

This classical gear train builds pretty high, but allows large wheels, a large mainspring barrel and so allows better precision.

side view of the gear train

side view of the gear train

In the specimen shown here, there’s a golden toned two leg Glucydur screw balance, which is located in two Incabloc shock protection bearings. It beats with 18000 A/h and regulates a classical swiss lever movement. For adjustments, there’s a long regulator arm with scale on the balance cock.

FHF 251 dial side

FHF 251 dial side

On the dial side, this movement is stamped as “FHF 25”, which makes the correct identification quite difficult. Apart from the larger diameter of the base place, the movement is identical to the FHF 25, so for a watchmaker, it doesn’t matter, whether he orders parts for an FHF 25 or an FHF 251.

Of course, this movement has got a yoke winding system. The escapement wheel bearings are topped with cap jewels. It’s hard to find better made movements than this.

In the lab

The specimen shown here was resinified and came in a damaged and rusty case into the lab, so it only got an oil treatment to bring the movement back to life. With an amplitude of now up to 260°, this is perfectly OK for the archive and so no further service was neccessiary.

Technical data

Manufacturer:FHF
Caliber:251
Number of jewels:17
Escapement:Pallet lever
Balance types: Glucydur screw balance
Shock protection(s): Incabloc
Balance bearing / direction hairspring:Clockwise
Moveable stud:no
Adjust mechanism:Long regulator arm
Construction:
  • lever
  • escape wheel, seconds wheel, third wheel
  • center minute wheel
  • mainspring barrel
Construction type:solid construction
Winding mechanism:yoke winding system
Setting lever spring:3 hole(s)
Features:SCD
Functions:hour, minute, second
A/h:18000
Size:11 1/2''' (measured: 25,6mm)
Literature: Flume: 1949 I 52
Inventory number:15021

Usage gallery

Atlantic Milano gents watch

Atlantic Milano gents watch

This movement and watch is a donation from Erwin. Thank you very much!