Description

A 20^th Century American centre seconds lever by Hamilton in a silver open face case.  High quality 22 jewel 3992B model, damascened nickelled split three quarter plate keyless movement with going barrel. Plain cock with polished steel micrometer regulator.  Uncut balance with overcoil Elinvar-Exra hairspring.  Club foot lever escapement, escape and lever pivots with endstones.  Signed white dial with the broad Ministry arrow, centre seconds, bold black Arabic numerals and smaller numerals for the minutes, blue steel hands.  Plain nickelled open face case with screw back and bezel, marked “Keystone – Base Metal”.  The back marked with the broad Ministry arrow before the serial number and “Navigation Master Watch – Hamilton Watch Co.”.  “H.S.3” has been struck through and the middle line overstruck with a new number.  Glazed aperture to the mahogany deck box, brass clasp.