Movement record · United States
Illinois Sangamo Special
Partially verifiedHigh-grade bridge railroad movement
Technical specifications
- Diameter
- 16 size
- Height
- Not recorded in the sources consulted
- Jewels
- 21 to 23 depending on grade
- Frequency
- 18,000 vph (2.5 Hz)
- Power reserve
- Approx. 40 hours
- Winding
- Stem wind
- Setting
- Lever set
- Escapement
- Swiss lever
- Balance
- Compensation balance with micrometric regulation
- Complications
- Subsidiary seconds
Identification features
- Grade name engraved on the movement
- Elaborate damascening and gold jewel settings on higher grades
Known variants
- Sangamo
- Sangamo Special
- Bunn Special relations
Servicing notes
Cleaning, lubrication, mainspring and pivot work belong with a qualified watchmaker working from calibre-specific documentation. Conserve original parts: replacing a worn component with a modern substitute changes the object, and refinishing plates or dials destroys evidence.
General guidance only. Antique movements should be serviced by a qualified watchmaker.
Historical significance
Among the most highly finished American railroad grades, and a benchmark for late American factory precision work.
Photographs



Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.
Sources & references
- de Carle, D., Watch and Clock Encyclopedia
- Period trade material catalogues and calibre reference compilations (edition-dependent)
- Published manufacturer technical documentation where available
Where sources disagree, the disagreement is stated rather than resolved silently.