Hamilton Grade 987A Pocket Watch Identification & Technical Specs
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⚙️ Convert This Pocket Watch Movement into a Custom Wristwatch
Have an authentic vintage Grade 987A mechanism? Our partner master atelier AntiqueWrist specializes in handcrafting solid .925 sterling silver wristwatch cases with welded wire lugs custom-fitted for this exact movement.
Enter the 5 to 8 digit serial number stamped directly on the movement plate (not the watch case):
Original Horological Blueprint • American Watchmaker Hamilton Grade 987A Movement Architecture
Technical Specifications & Factory Archival Records
Grade / Reference
Grade 987A
Movement Size
6/0s
Jewel Count
18 Jewels
Railroad Certification
Standard Grade (Non-Railroad)
Vibrations Per Hour
18,000 BPH (2.5 Hz)
Balance Lift Angle
52°
Power Reserve
37 hours
Escapement Type
Double roller lever escapement
Balance Wheel Construction
Monometallic balance
Hairspring Specification
Breguet overcoil hairspring
Shock Protection System
Rigid balance jewels
Horological Architecture & Collector Notes
The American Grade 987A 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 18 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.
