Complication · Timing
Small Seconds
VerifiedA subsidiary dial, usually below the centre, showing seconds independently of the main hour/minute display, driven directly off the fourth wheel of the going train.
Definition
A subsidiary dial, usually below the centre, showing seconds independently of the main hour/minute display, driven directly off the fourth wheel of the going train.
Historical origin
A natural consequence of the standard going train (centre, third, fourth wheel) once trains were geared to complete one revolution of the fourth wheel per minute; widespread from the eighteenth century as balance-based timekeeping accuracy made a seconds indication meaningful. No single inventor is credited.
How it works
In a conventional going-barrel or fusee train, the fourth wheel makes exactly one revolution per minute and normally carries the escape pinion. Rather than running the seconds hand from the centre arbor, the fourth-wheel pinion is extended through the dial (or a subsidiary dial plate) and a seconds hand is friction-fitted directly to it.
Because the fourth wheel is geared at a fixed ratio to the centre wheel, the seconds indication is mechanically simple and adds no extra parts to the going train — only the subsidiary dial, hand and sometimes a seconds bit (a small cap fitted over the pivot).
Small seconds is the layout found in the great majority of full-plate and three-quarter-plate movements before the mid-twentieth-century move to sweep (centre) seconds, since running the fourth wheel to the dial centre would have required an additional wheel and pinion.
Pocket watch context
The standard seconds arrangement on English, American and Swiss pocket watches, typically positioned opposite the pendant at 6 o'clock; its exact position (6, 9, or elsewhere) is a useful clue when assessing whether a dial and movement are original to each other.
Wristwatch context
Common on early and mid-twentieth-century wristwatches, and retained today as a deliberate vintage or dress-watch styling choice even where a centre-seconds train would be straightforward to fit.
Clock context
Found on many mantel and longcase clock dials as a small seconds ring above centre, again taken directly from the fourth wheel (or equivalent) of the clock's train.
Identification
- Seconds hand sits in its own recessed or printed subdial, not sharing the centre pinion
- On a full or three-quarter plate movement, a small seconds is the expected layout
- Position varies (6 o'clock is most common) and should match wear patterns on the dial
Servicing notes
Mechanically the simplest seconds display and rarely a service risk in itself, but a bent or over-tight seconds hand can drag on the dial and stop the watch. Complicated diagnosis (train depthing, pivot wear) belongs with a qualified watchmaker rather than home adjustment.
General guidance only. Complicated mechanisms should be assessed and serviced by a qualified watchmaker or clockmaker specialist, not adjusted at home.
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
- Britten, F. J., Old Clocks and Watches and Their Makers
- de Carle, D., Watch and Clock Encyclopedia
Where sources disagree, the disagreement is stated rather than resolved silently.