Movement record · United States (Lancaster, Pennsylvania)

Hamilton 4992B

Partially verified

A high-grade 16-size American movement built to a navigational specification, with a centre-seconds train and a plain, service-oriented finish rather than decorative damascening.

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Technical specifications

Diameter: 16 size
Height: Not recorded in a source consulted here
Jewels: 22 jewels
Frequency: 18,000 vibrations per hour
Power reserve: Approximately one day between windings
Winding: Lever-set keyless winding at the crown
Setting: Lever set, as required of a navigational watch
Escapement: Swiss lever
Balance: Jewelled, adjusted for temperature, isochronism and positions
Complications: Centre seconds, 24-hour dial on the standard military configuration

Identification features

Black 24-hour dial with centre seconds on standard military examples
Movement marked with the grade number and jewel count
Many surviving examples have been re-cased or re-dialled after military service
Black 24-hour dial with luminous hands in many examples
Movement marked 4992B, 22 jewels
Hacking (stop-seconds) feature when setting

Known variants

Contract variations in dial marking and case supplier
Pocket-watch and deck-box fittings
Post-war civilian and railroad conversions

Servicing notes

A well-documented movement with parts still circulating, but adjustment of a navigational-grade balance belongs with a professional watchmaker.

General guidance only. Antique movements should be serviced by a qualified watchmaker.

Historical significance

Second World War navigation-watch derivative of the 992B: 16-size, 22 jewels, with hacking seconds and a 24-hour dial, supplied to US and Allied forces for navigation and timing.

Watch, Navigation, Hamilton 4992B, AN5740 - DPLA - 94751f539b03394680385313113c84dc (page 1) — George H. Adamson Company, Hamilton Watch Co, CC0. Wikimedia Commons file page

Watch, Navigation, Hamilton 4992B, AN5740 - DPLA - 94751f539b03394680385313113c84dc (page 2) — Watch, Navigation, Hamilton 4992B, AN5740 - DPLA - 94751f539b03394680385313113c84dc (page 1) — George H. Adamson Company, Hamilton Watch Co, CC0. Wikimedia Commons file page

Sources & references

Hamilton collector reference literature and museum descriptions of military-issue examples
Individual issue dates cannot be established from the movement number alone.

Where sources disagree, the disagreement is stated rather than resolved silently.