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

Description — British Museum

Wrist-watch. 15 jewel Swiss movement with club-tooth lever escapement. Silvered dial with gold Arabic hour numerals and subsidiary seconds. Gold hands. Chromium-plated case with snap-on stainless-steel back. Black leather wrist-strap with chromium-plated buckle.

Curator's comments — British Museum

Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript) Made by Yeoman (movement by Enica S. A.) Switzerland, c. 1960. Wrist watch with a club tooth lever escapement. Signature: On the dial 'YOEMAN 15 JEWELS' and 'SWISS MADE'. Case: A round chromium plated three piece case with a snap on stainless steel back and a snap on bezel. Complete with a black leather strap with a chromium plated buckle. The case back inscribed 'FONTE INJECTEE' in a long rectangular cartouche and 'FOND ACIER INOXYDABLE 531'. Dial & Hands: A silvered metal dial with gold Arabic numerals and a sunk subsidiary seconds dial. Gold coloured hands of tapered baton style dial, gilt seconds hand. On the back of the dial in black is CM. The dial secured with two side screws. Movement: Ebauche Marks. An ebauche mark A-R in a lozenge and the number 412.(1) Frame: A round movement with nickel silver plates and with a grained finish. A bridge for the barrel one for the train and cocks for the pallets and balance. Barrel and Mainspring: Going Barrel: I diameter 9.2 mm., height 1.4 mm. Mainspring: height 1.2 mm., thickness 0.11 mm. Barrel Arbor: diameter 3.00 mm, snailed. Hooking: milled from the barrel wall. Train: All the brass wheels are gilded, the centre, 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. Ruby endstones to the balance jewels. Escapement: A straight line layout, club tooth lever escapement with short lever, double roller and D-shaped impulse pin. A steel escape wheel with four crossings. Exposed pallet stones, the acting faces flat. An equidistant locking escapement. No. of teeth embraced 3½. Balance & Spring: A monometallic balance with a 'self compensating' balance spring. Balance diameter 9.73 mm., thickness 0.72 mm. A flat spiral spring with 10 ½ turns. Means of Regulation: An index on the balance cock registers against a divided scale with 'F S' and 'A R' engraved on the balance cock table. Train Counts and Beat Rate: Great wheel (barrel) 70 Centre wheel 80 pinion 19 Third wheel 60 pinion 10 Fourth wheel 60 pinion 8 Escape wheel 15 pinion 6 Beat rate 18,000 Motion work: cannon pinion 10 minute wheel 30, minute pinion 8 hour wheel 32 Winding System: Conventional positive stem set keyless work. Dimensions: Diameter of bezel 30 mm., height 9.0 mm., over the glass. Movement: Diameter 23.6 mm., height 6.3 mm. Provenance: Donated in 1983 by The Heron Corporation Ltd. Note: (1) This is an Enica S.A. movement.