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Illinois Bunn Special 60hr Pocket Watch Identification & Technical Specs
Guild Home > Archive > Illinois Bunn Special 60hr Pocket Watch Identification & Technical Specs

Serial Number & Production Dating Lookup

Enter the 5 to 8 digit serial number stamped directly on the movement plate (not the watch case):

AMERICAN WATCHMAKER • American Watchmaker Illinois Bunn Special 60Hr DIAMETER: 42.4 mm | JEWELS: 21 Jewels | FREQ: 18,000 BPH ARCHIVE SPEC
Original Horological Blueprint • American Watchmaker Illinois Bunn Special 60Hr Movement Architecture

Technical Specifications & Factory Archival Records

Grade / ReferenceBunn Special 60hr
Movement Size16s
Jewel Count23 Jewels
Railroad Certification✓ Certified Railroad Grade
Vibrations Per Hour18,000 BPH (2.5 Hz)
Balance Lift Angle50°
Power Reserve36 hours
Escapement TypeDouble roller lever escapement
Balance Wheel ConstructionBimetallic compensation balance with gold screws
Hairspring SpecificationBlued steel Breguet spring
Shock Protection SystemNone (Solid jewel settings)

Horological Architecture & Collector Notes

The American Bunn Special 60hr was engineered to meet rigorous American horological standards during the turn of the 20th century. Utilizing high-grade alloy components, a precision Double roller lever escapement, and 23 jewels with fine ruby endstones, this movement provided exceptional isochronism and positional stability.

Among vintage restorers and conversion specialists, this series is admired for its accessible gear train geometry and solid metallurgy, making surviving specimens excellent candidates for preservation and custom recasing. For examples of restored and converted specimens, see Explore AntiqueWrist.

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