Mechanical Hand-Winding Movement Sonceboz ES 55, Voumard – NOS #4

Sonceboz ES 55?
(not sure, it could also be ES 54)

Mechanical Sonceboz ES 55 hand-winding movement, NOS, 17 jewels, 21600 A/h, approx. 27.0 mm diameter. Hard to find as a replacement movement.

Scope of delivery: 1x Sonceboz ES 55 (ES54)

Hand-winding movement

Diameter: approx. 27.0 mm (12“`)

17 jewels / 21600 A/h / from the 70s

Hardly available anymore as a replacement movement

New Old Stock, working well,

Height: 4.9 mm (from bottom to the top of the date dial guard)

Shock-protected / quick date adjustment

Pin lever escapement

Almost impossible to find

Comes in the original plastic box

Some useful information from the web (from the ranfft website),

but it has not been checked for correctness:
Dm = 26.6 mm, Do = 27.0 mm
F = 0.65 mm
T = 1.9 mm

Do outer diameter, thus the largest. Most movements have a flange a little bigger than Dm,

to rest on the case band or mounting frame.

Dm mounting diameter. With this diameter the movement fits into the aperture of the case or mounting frame
F mounting height, distance between dial plane* and mounting flange.

T stem height, distance between dial plane* and stem center

*) Movements with display discs on the dial side (e.g., calendar) occasionally have no dial support.

In this case the surface of the discs is taken as reference plane for H, F, and T.

If a dial spacer that is not permanently fixed is supplied with the movement, its additional height is stated.

Hands
1.50 x 0.90 x 0.20 mm

Since the movement is almost 50 years old, it must be serviced by a watchmaker before installation

Due to the long storage time, small traces may have formed on the movement, but this has no effect on the function.

A fine adjustment might be necessary.