Hamilton 500
ProbableHistorically the most important movement Hamilton ever made and, in service, among the least reliable. The contact system fouled and failed, and Hamilton replaced large numbers under warranty and service with the revised 505. That replacement programme is the single most important fact for anyone examining a 1957-59 Ventura: a 505 in an early case is the expected finding.
Specifications
- Movement manufacturer
- Hamilton
- Production
- 1957–1959
- Winding
- manual
Architecture
The first commercially produced electric wristwatch movement: a battery drives a balance wheel directly through an electrical contact system, with no mainspring and no motor. Mechanical gear train, electrically impulsed balance.
Authentication notes
- MovementProbable
A 505 in a 500-era watch is a service configuration, not a marriage
Classify it as a manufacturer service replacement. The correctness vocabulary exists for exactly this case: the part is not original to the watch, it was fitted by the manufacturer, and it is neither a defect nor a finding against authenticity. A surviving original 500 is rarer and worth more precisely because so many were replaced.
Production revisions
- 1959Probable
Superseded in production and in service by the caliber 505
The 505 revised the contact arrangement that caused the 500's failures. It replaced the 500 in production and was also fitted to existing watches through Hamilton's service network, which is why the caliber found in an early Ventura frequently post-dates its case.
Service practice
Specialist work. The contacts and the coil are the failure points, original parts are scarce, and few watchmakers take these on. A non-running electric Hamilton is common and is not evidence against the watch.
Related calibers
Preceded by
Hamilton 505
References using this caliber
American Classic · 1957–1959
Provenance of this record
Sources & Evidence
Hamilton collector research on the electric calibers, named models and case reproduction
Collector communities and specialist dealers
- Accessed
- 2026-08-19
Cited for
NAWCC message board and encyclopedia material on Hamilton Watch Company production
National Association of Watch and Clock Collectors
- Accessed
- 2026-08-19
Cited for
Last verified: Not yet reviewed