Component record · Train
Centre Wheel
VerifiedThe second wheel in the going train (after the barrel), usually running once per hour, from which the minute hand is normally driven via the motion works.
What it does
Passes power from the barrel deeper into the going train and provides the once-per-hour rotation used to display minutes.
How it works
The centre wheel's pinion meshes with the barrel teeth (or fusee great wheel), and its own larger wheel meshes with the third wheel pinion, continuing the train toward the escapement. Because it commonly rotates exactly once per hour by design, its arbor is a convenient take-off point for the minute display.
The cannon pinion, which carries the minute hand, is usually mounted with light friction directly on the centre-wheel arbor's extension so the hands can be independently set without disturbing the going train's gearing.
Its position — literally central on many plate layouts — also gives the wheel its name, though its arbor is not always at the geometric centre of the movement in every calibre design.
Evolution
Architecturally stable across almost all mechanical watch and clock designs since the wheel train was standardised.
Known variations
- Standard hour-per-revolution centre wheel
- Centre-seconds designs where a different wheel is relocated to the centre for a sweep seconds hand
Identification for collectors
- Identifiable as the wheel whose arbor projects to the dial side to carry the cannon pinion and minute hand
Common failure modes
- Worn pivots causing wobble or increased friction
- Bent or damaged teeth from shock
Related photographs
No confidently matched photograph of this subject has been found yet. These photographs show a closely related record, and are not examples of the type described on this page.
Sources & references
- Daniels, G., Watchmaking
Where sources disagree, the disagreement is stated rather than resolved silently.