Gold-filled cased club-tooth lever wrist-watch

Description — British Museum

Wrist-watch. Circular 7 jewelled Swiss movement with club-tooth lever escapement. Silvered brass dial has Arabic hour numerals and subsidiary seconds. Rectangular gold filled case. Keyless winding and hand setting. Complete with 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 V (Unpublished manuscript) Made by Ingersoll Switzerland, c. 1929 Wrist watch with a club tooth lever escapement. Signature: On the dial 'INGERSOLL' and 'SWISS MADE'. Case: A rectangular 3 piece rolled gold case with inscribed in the back "Presented to MR A. L. BENZING to record 5 years in the employ of THE HOUSES OF INGERSOLL LONDON January 26th 1929". The bezel and back are hinged to a central piece which carries the lugs and also houses the movement. In the case back is an incuse G. Also 'GOLD FILLED CASE GUARANTEED 10 YEARS MADE IN SWITZERLAND'. In a cartouche is 'I W CO LD' and in another cartouche is 'M.B. 1930 P.O.G.' The watch complete with a brown leather strap. Dial & Hands: A silvered dial with Arabic numerals, these once luminised and skeletonised hands also luminised. The seconds hand of blued steel. The dial secured with two dog screws. Movement: Ebauche Marks: Stamped on the front plate is 37, this is also stamped under the balance cock so is more likely to be a number used during production. Frame: A round movement with a nickel plated brass frame with on the barrel bridge '7 JEWELS' on the barrel ratchet wheel 'INGERSOLL', two dots and a star. On the winding wheel is 'SWISS MADE' and a star. A bridge for the barrel, the winding work and the centre wheel, a bridge for the third and fourth wheels and cocks for the escape wheel, the pallets and the balance. Barrel and Mainspring: A recessed cover to the going barrel. Barrel: I diameter 9.3 mm., height 1.4 mm. Mainspring: height 1.4 mm, thickness 0.12 mm. Barrel Arbor: diameter 3.0 mm., snailed. Hooking: milled from the barrel wall. Train: All the brass wheels are gilded, the centre wheel, third and fourth wheels with five crossings. The steel escape wheel with four. Jewelling: Jewel bearings only at the balance. 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. 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: an uncut monometallic balance with brass screws. Balance diameter 8.9 mm., thickness 0.60 mm. A blued-steel flat spiral spring with 10 1/3 turns. Means of Regulation: An index on the balance cock registers against a central arrow with 'F S' and 'A R' engraved on the balance cock table. Train Counts and Beat Rate: Great wheel (barrel) 70 Centre wheel 64 pinion 10 Third wheel 60 pinion 8 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: Case length 36 mm., width 25 mm., height 9.7 mm over the glass. Movement: diameter 23.6 mm., height 6.1 mm. Provenance: Donated in 1983 by The Heron Corporation Ltd.