Girard-Perregaux 31.29

Automatic · 11.5‴ · Switzerland · 1965

Dimensions
26 mm
Height
5.00mm
Jewels
39
Power reserve
40h
Timegrapher
Beat rate
21,600bph
Frequency
3Hz

Reference: healthy amplitude ≈ 270–315° fully wound (>200° at 24 h); beat error ideally < 0.5 ms.

Movement
Movement type Automatic
Winding type Automatic (Rotor-Driven)
Setting type Stem Set (Crown Pull)
Escapement type Swiss Lever
Control type Balance Wheel
Regulator type Pinned Regulator (or Index Regulator)
Rotor type Central Rotor
Shock protection Incabloc
Specifications
Lignes 11.5‴
Shape Round
Complications Sweep Second
Hand count 3
Hand sizes 1.50 x 0.90 x 0.21mm
Further measures
Mounting Diameter (Dm): 25.6mm
Stem height (T): 1.7mm
Mounting Height (F): 1.1mm
Origin & References
Manufacturer Girard-Perregaux
Country Switzerland
Launch year 1965
COSC certified No
Signature
ca. 1965: 3219279, Girard-Perregaux, Gyromatic, Swiss, 39 Jewels; Incabloc (Girard-Perregaux 32.19)
US import codes
Notes
Remarks: automatic with two roller freewheels
ball-bearing rotor
regulation gear
The family is based on the manual wind calibre AS 1687/1688.
The automatic mechanism is a joint development of Doxa, Eberhard, Favre-Leuba, Girard-Perregaux, and Zodiac.
differences not known between 31.19, 31.29, 31.4, 31.9
Other data: balance staff: U2839 stem: W2837 mainspring / battery: 1.10 x 10.0 x 0.11mm
Ranfft mentioned about this caliber: There are variants with this quantity of jewels 17, 39