Nickel-chromium-plated cased pin-pallet lever wrist-watch with wrist-strap

Description — British Museum

Ingersoll Dot wrist-watch. Movement with pin-pallet lever escapement; keyless winding and hand-setting. White printed paper dial with Arabic hour numerals and subsidiary seconds. Blued-steel hands. Nickel-chromium plated case. Complete with wrist-strap of woven grey thread and leather.

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 V (Unpublished manuscript) Made by Ingersoll Switzerland, c. 1960 Wrist watch with a pin pallet lever escapement. Signature: On the dial 'INGERSOLL DOT' and 'SWISS MADE'. Case: A round chromium plated two piece case with a snap on bezel. Complete with a strap of woven grey thread and leather. Dial & Hands: A silvered metal dial with black Arabic numerals and minute circle and a subsidiary seconds dial. Blued steel hands. The dial secured with screws one at 12 and the other at 6 o'clock. Movement: Ebauche Marks.: None. Frame: A round movement with nickel silver plates with a Geneva stripe finish signed on the back plate 'INGERSOLL' and 'SWISS MADE' The back plate is supported by the keyless block and two pillars and secured by screws. Both the pallet and the balance cock are mounted on the back plate. Barrel and Mainspring: The steel barrel cover caries the slipping minute wheel. Barrel: internal diameter 12.0 mm., height 1.6 mm. Mainspring: height 1.4 mm, thickness 0.13 mm. Barrel Arbor: diameter 3,3 mm., snailed. Hooking: A tongue punched in from the barrel wall. Train: The brass wheels not gilded, the second, third and fourth wheels with five crossings. The escape wheel with four. Jewelling: Jewels at the balance pivots only, steel endplates. Escapement: An obtuse angle layout pin pallet lever escapement with a long lever, and a brass impulse finger. Steel pins. The escape wheel with four crossings. An equal impulse escapement. No. of teeth embraced 3½. Balance & Spring: A single arm balance with nibs to resemble screws. Balance diameter 8.18 mm., thickness 0.63 mm. A blued-steel flat spiral spring with 9 ¾ turns. Means of Regulation: An index on the balance cock registers against a divided scale with 'A R' stamped on the balance cock. Train Counts and Beat Rate: Great wheel (barrel) 96 (Rotates in four hours) Second wheel 40 pinion 10 (Rotates in 25 minutes Third wheel 50 pinion 8 (Rotates in 5 minutes) Fourth wheel 60 pinion 10 (Rotates once a minute) Escape wheel 15 pinion 6 Beat rate: 18,000 Motion work: cannon pinion 10 minute wheel 40, minute pinion 12 hour wheel 36 Winding System: Conventional positive stem set keyless work. Dimensions: Case diameter 25.5 mm. Height 9.8 mm., over the glass. Movement: Diameter 23.8 mm., height 7.0 mm. Provenance: Donated in 1983 by The Heron Corporation Ltd. Note: (1) This is a similar but not identical movement to registration no. 1983,1012.169.