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View picture in original size
Fig. 1

View picture in original size
Fig. 2

Gruen 311 Curvex

manual wind
sub second

7.75 x 11.75''', Dm= 17.65 x 26.4mm
17 jewels
f = 18000 A/h
power reserve 40h

Balance staff U2415

Stem W2162

Mainspring / battery
1.18 x 8.5 x 0.105 x 250mm
~Zf665, 1.20 x 8.5 x 0.095 x 265mm

1.22 x 0.66 / 0.16mm

Comments about the data

(Alpina Gruen Gilde 1929-1937)
first Curvex calibre
bimetallic screw balance, Breguet hairspring
Conoruma is Gruen's proprietary alloy for hairspring and balance with low temperature dependence

311: Curvex, curved back surface
355: flat dial surface, plane back surface
355C: curved dial surfce, plane back surface

Example, year: signature; shock device
1937: 310608, Gruen Watch Co, Precision, Switzerland, Coronuma Hrsp. & Bal., 17 Jewels

© R. Zeller

Not for Sale!
The movements presented in this caliber finder are not for sale. This is only a data sheet for identification and evaluation of the movement calibre, as well as for approximate dating.

bidfun-db 21.3 © 02-08-15, mtr-Ranfft

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