Movement record · Switzerland
ETA 6497
Partially verifiedLarge hand-wound pocket-watch-derived layout with small seconds at 6 o'clock; the Unitas 6497 lineage is one of the last widely produced pocket-watch-sized ébauches.
Technical specifications
- Diameter
- Approx. 36.6 mm (16½ lignes)
- Height
- Approx. 4.5 mm
- Jewels
- 17 jewels in standard form
- Frequency
- 18,000 vph (2.5 Hz) in classic form; later variants differ
- Power reserve
- Approx. 46–53 hours depending on version
- Winding
- Hand-wound
- Setting
- Stem setting
- Escapement
- Swiss lever
- Balance
- Monometallic with Nivarox-type spring in modern versions
- Complications
- None
Identification features
- 16½-ligne size far larger than ordinary wrist calibres
- Small seconds at 6 with the fourth wheel directly below centre
- Unitas/ETA signature on the train bridge
Known variants
- ETA 6498 (seconds at 3, hunter layout)
- Unitas-branded earlier versions
- Decorated and chronometer-graded variants
Servicing notes
Cleaning, lubrication, mainspring and pivot work belong with a qualified watchmaker working from calibre-specific documentation. Conserve original parts: replacing a worn component with a modern substitute changes the object, and refinishing plates or dials destroys evidence.
General guidance only. Antique movements should be serviced by a qualified watchmaker.
Historical significance
The 6497/6498 family is the standard modern large hand-wound ébauche and the movement most watchmaking schools use to teach disassembly and adjustment, making it a reference point for understanding traditional going-train layout.
Diagram
Sources & references
- de Carle, D., Watch and Clock Encyclopedia
- Period trade material catalogues and calibre reference compilations (edition-dependent)
- Published manufacturer technical documentation where available
Where sources disagree, the disagreement is stated rather than resolved silently.