Movement record · United States
Illinois Bunn Special (60-hour grades)
Partially verifiedThree-quarter plate railroad-grade movement with a long-running barrel arrangement marked for a 60-hour run, produced in the final independent years of the Illinois Watch Company.
Technical specifications
- Diameter
- 16 size
- Height
- Not consistently documented across grades
- Jewels
- 21 or 23 depending on grade
- Frequency
- 18,000 vph (2.5 Hz)
- Power reserve
- Marked as approximately 60 hours, from which the grades take their collector name
- Winding
- Stem wind
- Setting
- Lever set on railway-service examples
- Escapement
- Swiss lever with jewelled pallets
- Balance
- Compensation balance with micrometric regulator
- Complications
- Subsidiary seconds
Identification features
- '60 Hour' marking on the movement alongside the Bunn Special grade name
- Motor-barrel style long-run barrel
- Lever set, as required for railway service in this period
Known variants
- 21-jewel grades
- 23-jewel grades
- Examples finished or assembled after Hamilton acquired Illinois
Servicing notes
Parts are scarcer than for Hamilton equivalents, and correct replacement barrels in particular are difficult to source. Movement work belongs with a watchmaker familiar with American railroad grades.
General guidance only. Antique movements should be serviced by a qualified watchmaker.
Historical significance
One of the most sought-after American railroad grades, and the standard example cited when discussing extended power reserve in service watches.
Related photographs
.jpg)
.jpg)
.jpg)
No confidently matched photograph of this subject has been found yet. These photographs show a closely related record, and are not examples of the type described on this page.
Sources & references
- Illinois Watch Company factory literature as reproduced in NAWCC publications
- Grade-by-grade production totals differ between published sources and are given here only as ranges.
Where sources disagree, the disagreement is stated rather than resolved silently.