Chrome-plated cased club-tooth lever watch with imitation leather wrist-strap

Description — British Museum

Wrist-watch. Movement with club-tooth lever escapement; balance assembly and balance cock now missing; glass missing. Silvered dial with baton hour marks, a circle for minutes and centre-seconds; to right an aperture for for date indication. Silver coloured hands. Chromium-plated case with snap-on back. Complete with imitation leather wrist-strap.

Curator's comments — British Museum

Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript) Made by Ingersoll Switzerland, c. 1960 A centre seconds wrist watch with date and a club tooth lever escapement. Signature: On the dial 'INGERSOLL 17 JEWELS SHOCK RESISTANT SWISS MADE' On the barrel bridge Amida and the trade mark repeated. Case: A basically round chromium plated two part case with a snap on back. The case back inscribed 'STAINLESS STEEL BACK SHOCKPROOF SWISS MADE 91469' and a mark of two wings flanking a W with beneath 'WINGO'. The glass is missing. Complete with an imitation black leather strap but with a gilt buckle. Dial & Hands: A silvered dial with rhodium plated baton hour marks with a black stroke at the centre, the three intermediate minutes between each baton marked in black. At 3 o'clock there is a date aperture. Rhodium plated hands, the baton minute and hour hands also with a black central stoke. The seconds hand is also rhodium plated. Movement: Ebauche Marks. On the barrel bridge is Amida and the Amida trade mark and SWISS inside of the front plate is the name of Amida and under also the calibre number 561. Frame: Nickel silver plates with a bridge for the barrel, another for the train. A cock for the pallets and one for the balance this latter now missing. A cock for the centre seconds pinion. A drag spring for taking up the backlash in the centre seconds pinion. Barrel and Mainspring: A recessed cover to the going barrel. Barrel: I diameter 7.8 mm., height 1.4 mm. Mainspring: height 1.3 mm., thickness 0.125 mm. Barrel Arbor: diameter 2.2 mm., snailed. Hooking: milled from the barrel wall. Train: The brass wheels are not gilded, the centre, third and fourth wheels with five crossings. The steel escape wheel with four crossings. Jewelling: Jewelled bearings from the third wheel onwards, also the centre wheel bearing in the front plate is jewelled. All the jewels are pressed in. An endstone for the front escape wheel and pallet holes. The cock for the centre seconds pinion is jewelled. A shock protected jewel for the balance staff in the front plate. A jewel pin in the hour wheel indexes the date wheel which is itself mounted on a jewel pin. There is a flat cylindrical jewel acting as the jumper for the date disc. Also the barrel arbor hole is jewelled in the front plate. Escapement: A straight line layout club tooth lever escapement with long lever, there would have been a double roller and no doubt a D-shaped impulse pin. A steel escape wheel with four crossings. An equidistant locking escapement. No. of teeth embraced 3½. Balance & Spring: The balance assembly missing. Train Counts and Beat Rate: Great wheel (barrel) 75 Centre wheel 64 pinion 12 Third wheel 60 pinion 8 Fourth wheel 60 pinion 8 Escape wheel 15 pinion 6 Centre pinion driving wheel 75. Idle centre seconds pinion 10 Beat rate 18,000 Motion work: cannon pinion 12, minute wheel 32, minute pinion 8, hour wheel 36. Date work: The date disc is driven through the agency of two wheels, the first is indexed by the hour wheel once every 12 hours and has 10 teeth. The second which is driven by the 10 tooth wheel has 6 teeth but with three longer than the others. It is these three long teeth that index the date wheel every 24 hours. Winding System: Conventional positive stem set keyless work. Dimensions: Case diameter 22.0 mm., height 7.2 mm., over the glass. Movement: diameter 19.6 mm., height 6.3 mm. Provenance: Donated in 1983 by The Heron Corporation Ltd.