Felsa 4122

 
Felsa 4122 |

Felsa 4122

Description

In the early 1960s, Felsa released their series of tiny, 7 3/4 ladies’ watch calibers, the caliber series 21600, to which the caliber Felsa 4122 shown here belongs. It has got a screw-less balance and beats already semi-fast with 21600 A/h.

Felsa 4122: base plate

base plate

The quality is good, as always on Felsa movements. Thanks an (only on the movement side) ruby beared minute wheel and a cap jewel for the escapement wheel bearing (also only on the movement side), it could be advertized with 17 jewels.

Felsa 4122: gear train

gear train

The Felsa 4122 uses the traditional gear train, consisting of mainspring barrel, center minute wheel, third wheel, decentral seconds wheel at 6 o’clock and the escapement wheel which is controlled by a swiss pallet lever.

On the specimen shown here, the prolonged seconds wheel was shortened in a crude way.

If there also exists a version without prolonged seconds wheel is not yet known.

Felsa 4122: side view of the gear train

side view of the gear train

The modern anular balance with three legs and without screws is not yet shock protected, but already works with 21600 A/h.

Only directly at the hairspring key, the effective length of the hairspring is adjusted.

Felsa 4122: Felsa 4122: Dial side

Felsa 4122: Dial side

The bevel on the edge (both on the dial and on the movement side) means that a little height can be saved on the already quite flat movement, which is only 2.9 mm, because at the time there was a great demand for particularly flat watches.

In the lab

This movement came without case into the lab and got a simple service.

Timegrapher result

Despite the small size and obviously not always good treatment (visible, among other things, in a slightly wobbly balance wheel and an amateurishly shortened seconds hand axle), the timegrapher rates ​​are very decent, but at the same time show the potential that this movement would have in really good condition.

horizontal positions
dial up -30 s/d 229° 0.5ms
dial down -4 s/d 224° 0.2ms
vertical positions
crown right (12 up) +1 s/d 185° 0.2ms
crown up (3 up) -11 s/d 179° 0.0ms
crown left (6 up) -5 s/d 193° 0.3ms
crown down (9 up) +30 s/d 196° 0.7ms

Technical data

Manufacturer:Felsa
Caliber:4122
Caliber base:Felsa 4020
Size:7 3/4''' (measured: 17,25mm)
Height:2,9mm
A/h:21600
lift angle:52°
Number of jewels:17
Escapement:Pallet lever
Balance types: monometallic anular balance (three legs)
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:solid construction
Winding mechanism:yoke winding system
Setting lever spring:2 hole(s)
Attachment of setting lever:screwed
Features:
  • s (decentral seconds) (optional)
References: Flume: K2 2
Inventory number:23062

Usage gallery

Felsa 4122: Atrexa ladies' watch  (case missing)

Atrexa ladies' watch (case missing)

This movement is a kind donation from Peter Kern to the movement archive. Thank you very much for your great support!