Glossary · Mechanism
Centre wheel
The train wheel, usually turning once per hour, that carries the minute hand via the cannon pinion.
Explanation
The centre wheel is the train wheel normally driven by the barrel and arranged to turn once per hour. Its arbor commonly carries the cannon pinion and minute hand through friction, which makes it a key link between the going train and the display. The name describes its conventional function more than a guaranteed geometric position in every calibre.
Layout variations matter. Indirect centre seconds, off-centre displays, thin automatic movements and some clock trains can put the relevant wheel away from the dial centre or add intermediate gearing. For condition, centre-wheel pivots and holes carry heavy load and are common wear points in old clocks and watches; bushing or pivot work must be recorded as treatment, not hidden as routine cleaning.
Sources & references
- de Carle, D., Watch and Clock Encyclopedia — train terminology
- Reymondin et al., The Theory of Horology — going train
Where sources disagree, the disagreement is stated rather than resolved silently.
What to record
- Confirm whether the wheel actually turns once per hour.
- Record how the cannon pinion is fitted and whether seconds are indirect.
- Look for documented bushing or pivot repairs in service records.
Do not remove hands or dial to inspect the motion work unless you are equipped to do so safely.
In the object catalogue
Catalogued objects whose own source record mentions “Centre wheel”. The quoted line shows where; it is the seller’s or museum’s wording, not independent verification.
