Felsa 4007

 
Felsa 4007

Felsa 4007

Description

In the late 1950s, Felsa released their one but least series of selfwinding movements, which can be seen as the climas of the Felsa movement development. Without competition of battery (electromechanical and quarz) powered movements, it could still be drawn from the full in terms of construction.

The Felsa 4007 is the version with date indication and semi-fast quickset mechanism. Compared with the caliber 4002, the selfwinding mechanism was reworked a bit.

base plate

base plate

As expected from Felsa, all important bearings use rubies.

inside the gear train bridge

inside the gear train bridge

Probably to save space, probably to avoid interference with the selfwinding mechanism, the crown wheel was put onto the inner side of the gear train bridge.

gear train

gear train

The Felsa 4007 uses the classical geare train:
The mainspring barrel drives the center minute wheel, which is beared under its own bridge. Afterwards, the double third wheel, seconds wheel at 6 o’clock (which, in theory, could carry a decentral seconds hand) and steel escape wheel follow.

The double third wheel engages with the center seconds pinion without a need for a spring to avoid fluttering of the center second hand.

side view of the gear train

side view of the gear train

The Felsa 4007 already uses a three leg anular balance without screws. It is beared between to Incabloc shock protections and beats with slow 18000 A/h. Unfortunately, it can be regulated only directly at the hairspring key.

without selfwinding mechanism

without selfwinding mechanism

Unlike the Felsa 4002, the gears of the selfwinding mechanism are mounted directly into the gear train bridge, and no longer in an own, detachable module.

gear train selfwinding mechanism

gear train selfwinding mechanism

The selfwinding mechanism is pretty simple, but geniuos. The main element in the rocking bar changer with two connected gears. Depending on the turning direction of the oscillating weight, either the upper or the lower gear engages with the transmission wheel. This, together with the ratchet ensures, that this ransmission wheel always revolves in the same direction and winds, by using a second reduction gear, the mainspring by engaging with the crown wheel.

missing oscillating weight

missing oscillating weight

The oscillating weight is axle beared and contains a ruby bearing for the axle.

inside oscillating weight

inside oscillating weight

The yet empty dial side shows the yoke winding system with its very rugged executed setting lever spring also the preparations for the calendar mechanism:

empty dial side

empty dial side

The calendar mechanism is a very simple construction: The hour wheel drives a tiny transmission wheel, which drives the date switching wheel.

transmission wheel

transmission wheel

The date ring advances semi-fast between 11pm and midnight and can be corrected by turning the time back to 10pm and forth.

calendar mechanism

calendar mechanism

As common for Felsa, the transmission wheel of the calendar mechanism is secured by a small plate, which is also one of the three securing plates for holding the date ring in position.

Felsa 4007: Dial side

Felsa 4007: Dial side

How well the Felsa 4007 really was, can be seen on the timegrapher results in the lab:

In the lab

The specimen shown here came gummed into the lab, and at least on the dial, you could see, that it was not treated well. The case was missing, it most certainly was a golden case, which was destroyed recently by melting it, although Kelek is a known upper class manufacturer.

The movement got a simple service with cleaning, oling and adjusting.

Timegrapher result

The rates of this “slaughter movement”, which certainly was torn off a golden watch and not handled with care, are nothing but sensational.
In all positions, it runs perfect within the chronometer speficiation, especially the maximum deviation of four seconds over all positions is fantastic; the COSC certification would allow a devation of ten seconds here.
Of course, these numbers are only snapshots, and the low amplitude shows, that they won’t last forever, but they impressively show, how good the quality of Felsa movements was.

horizontal positions
dial up +2 s/d 233° 0.7ms
dial down +2 s/d 257° 0.0ms
vertical positions
crown right (12 up) -2 s/d 222° 0.5ms
crown up (3 up) +1 s/d 226° 0.8ms
crown left (6 up) +2 s/d 212° 0.1ms
crown down (9 up) +2 s/d 224° 0.3ms

Technical data

Manufacturer:Felsa
Caliber:4007
Caliber base:Felsa 4000
Size:11 1/2''' (measured: 25,9mm)
Height:5,55mm
A/h:18000
Number of jewels:21
Escapement:Pallet lever
Balance types: Nickel anular balance (three legs)
Shock protection(s): Incabloc
Balance bearing / direction hairspring:Clockwise
Moveable stud:yes
Adjust mechanism:Hairspring key
Construction:
  • lever
  • escape wheel, seconds wheel, third wheel, center second pinion
  • center minute wheel
  • mainspring barrel
Construction type:solid construction
Winding mechanism:yoke winding system
Setting lever spring:1 hole(s)
Features:
  • SCI (indirect center seconds)
  • QG (date indication (aperture))
  • RDR (date corrector)
  • AUT (selfwinding)
Literature: Flume: K3 -
Inventory number:20053

Usage gallery

Kelek gents watch (case missing)

Kelek gents watch (case missing)