CEH – Swissonic #1581, Prototype, 1967
Categories: functional prototype
Description: Stainless steel cased prototype. Stainless steel case back, inside stamped with prototype number ‘1581’ and ‘FB’ standing for ‘François Borgel’, see below. The prototype number ‘1581’ is also embossed on one of the surfaces facing the lugs. Anthrazite coloured brass dial with raised 5 minute markers, white peripherial minute track with black printed minute marks. White printed ‘Swissonic’ at ’12’ and ‘Swiss’ at 6′. Date window at ‘3’. Silvered, thin hour, minute and seconds hand. Acrylic crystal. Anonymous stainless steel crown.
Dimensions: 36.2mm (without crown), lug – lug: 41.3mm, lug width: 18mm
Movement: Prototype cal.: 153
Additional info: The adjustment devices on the arms of the tuning forks are little metallic hooks, earlier prototypes have small excentric screws for adjusting the frequency.
Case was made by ‘Taubert Fils’, who still used the mark ‘FB’ for François Borgel, who invented this type of watch case. The main case is unmarked, the ‘FB’ mark is stamped on the inside of the screw down case back.
Picture credit: P. Pasierbeck
Electric Watch Prototypes 