Chrome-plated cased jewelled club-tooth lever centre-seconds alarm wrist-watch with date mechanism

Description — British Museum

17-jewel movement with club-tooth lever escapement and alarm mechanism. Blue-painted metal dial with luminous-painted bars at 3, 6, 9 and 12; date aperture at 3 o'clock. Steel hour, minute and centre-seconds hands; alarm-setting hand with arrow-head pointer. Chromium-plated case with screw-on stainless-steel back.

Curator's comments — British Museum

Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript) SICURA S.A. Switzerland, c. 1945 Wrist Watch with alarm, date work and a club tooth lever escapement Signature: On the dial 'MEMOSTAR ALARM' On the train bridge 'SICURA S.A.' Case: A toneau three piece case, the front base metal and the back steel. The bezel is shaped so as to conform to the oval glass. The back is retained by a screwed ring and is engraved 'BASE METAL BEZEL SWISS MADE STEEL BACK WATER RESISTANT'. The back has a post riveted in it for the hammer to hit. Dial & Hands: The blue dial has white hour batons and minute marks - these are unusually long. The hour marks at 12, 3, 6 and 9 are heavier than the others and are luminised. An aperture at 3 o'clock for the date. The date ring has black numerals on a white background. Skeleton baton style hands rhodium plated and a rhodium plated centre seconds hand. The alarm hand has an arrow shaped tip painted red. Movement: A nickel silver movement.(1) Ebauche Marks: Frame: A bridge for the going barrel and keyless work, this is engraved 'SWISS'. A bridge for the alarm barrel and train. one for the centre wheel and another for the going train, this engraved 'SICURA S.A. 17 JEWELS'. Cocks for the pallets and balance. Barrels and Mainsprings: Going Barrel: I diameter 9.2 mm., height 1.5 mm. Mainspring: height 1.5 mm., thickness 0.11 mm. Barrel Arbor: diameter 2.95 mm., snailed. Hooking: Milled from the barrel wall. Alarm Barrel: I diameter 8.2 mm., height 1.9 mm. Mainspring: height 1.9 mm., thickness 0.08 mm. Barrel Arbor: diameter 2.40 mm., snailed. Hooking: Milled from the barrel wall. Both barrel covers are recessed. Train: All the wheels gilded, the centre wheel, third and fourth wheels with five crossings. The steel escape wheel with four. Jewelling: Jewelled bearings from the third wheel onwards, all the jewels pressed in. Incabloc shock protection to the balance. The alarm train escape wheel pivots are jewelled and the lower pivot of the hammer. Escapement: A straight line layout club tooth lever escapement with short lever, double roller and D-shaped impulse pin. The exposed pallet stones have flat acting faces. A steel escape wheel with four crossings. An equidistant locking escapement. No. of teeth embraced 3½. Balance & Spring: a monometallic three arm balance with a plain rim. Balance diameter 9.7 mm, thickness 0.65 mm. A 'self compensating' flat spiral spring with 12 turns. Means of Regulation: An index with a pair of horns is on the balance cock and has a divided scale upon it with '+' and '-' but nothing indicates against this. There is an empty hole in the cock which once held the remainder of the micrometer adjusting device which is now missing. This is in its complete form in the watch by Vulcain registration no. 1989,0407.3. Train Counts and Beat Rate: Great wheel 70 (barrel) Centre wheel 64 pinion 10 Third wheel 60 pinion 8 Fourth wheel 70 pinion 8 Escape wheel 15 pinion 7 Beat rate 18,000 Motion work: cannon pinion 10 minute wheel 30, minute pinion 8 hour wheel 32 Winding System: There are two buttons, one for the alarm work and one for the going. The going train has conventional stem set positive keyless work but the alarm train has stem set rocking bar keyless work. Alarm System: A conventional alarm system where the hour wheel can rise when three lugs on it coincide with three slots in the alarm wheel and in rising frees the alarm train via a lever. Great wheel (Barrel) 78 teeth. Alarm wheel 14 pinion 7 Date Work: A sub plate carries the date ring and its jumper and jumper spring. Gearing from the minute pinion drives an idle wheel of 19 which in turn drives an intermediate wheel of 32 and a pinion of 16. This then drives the indexing wheel of 32. Dimensions: Case: length 41.2 mm., width 36 mm., height 13.6 mm., over the glass. Movement: diameter 25.5 mm., height 8.8 mm. Provenance: Purchased in 1989 with the aid of funds from the Dingwall Bequest. Note: (1) This is in fact a Vulcain movement.