Movement record · United States (Lancaster, Pennsylvania)
Hamilton 4992B
Partially verifiedA 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.
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
Known variants
- Contract variations in dial marking and case supplier
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
The American navigational pocket watch of the Second World War, and the movement through which high-grade American pocket watchmaking reached its final large-scale use.
Diagram
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.