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Illinois Serial Number 3000000-4000000 Date & Production Guide
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Serial Number & Production Dating Lookup

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

Technical Specifications & Factory Archival Records

Range3000000-4000000
Vibrations Per Hour18,000 BPH (2.5 Hz)
Balance Lift Angle50°
Power Reserve36 hours
Escapement TypeStraight line lever escapement
Balance Wheel ConstructionExpansion balance
Hairspring SpecificationBreguet overcoil hairspring
Shock Protection SystemRigid balance jewels

Horological Architecture & Collector Notes

The American pocket watch was engineered to meet rigorous American horological standards during the turn of the 20th century. Utilizing high-grade alloy components, a precision Straight line lever escapement, and 15 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 AntiqueWrist Studio.

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