Regulation · Entry 03
Six Positions
A watch runs differently on its back than on its edge. Why adjustment is done in several positions.
A watch behaves differently depending on where gravity finds it
Lay a watch flat on a table and it runs at a certain rate. Stand it on its edge — crown up, crown down, crown left, crown right — and it runs at a slightly different rate in each case. Adjust it only in one position and you have a watch that keeps time while resting in the watchmaker's tray and loses it on the wrist.
The cause is the balance wheel and its staff. No pivot runs perfectly in the exact centre of its jewel hole; there is always a tiny residual eccentricity. When the watch is vertical, gravity loads the pivot against the side of the jewel rather than the bottom, changing the friction and shifting the effective length of the hairspring's attachment. The result is a rate error that changes sign and magnitude as the watch rotates. A watch tested only dial-up might beat within a few seconds a day; stood crown-down it might gain fifteen.
The six standard positions are: dial up, dial down, crown up, crown down, crown left, and crown right — though in practice crown-left and crown-right are often treated as a pair, since a watch spends most of its working life alternating between roughly those two orientations on a moving wrist. Pocket watches, by contrast, spend most of their time crown-up and were traditionally adjusted to fewer positions as a result.
Adjustment across positions is largely a matter of the balance wheel's poise — the mass distribution around its rim — and the geometry of the lever and banking pins. A watchmaker corrects static poise by carefully removing or redistributing material on the rim. The escapement geometry is fixed, but careful poising removes the imbalance that magnifies the effect of the pivot's imperfection. This is painstaking work with a poising tool and a light touch: too much removed and you have introduced the opposite error.
A movement described as "adjusted to six positions" has been tested, measured and corrected so that the rate in each position lies within an accepted tolerance of the others. It is a certificate of care, not a claim of perfection — because gravity is still there in all six, and so are the pivots.
From the bench notes
What it means in practice
| Item | What it means |
|---|---|
| Six positions | dial up, dial down, crown up, crown down, crown left, crown right: the standard orientations in which a watch movement is tested and adjusted |
| Poise | the balance of mass around the balance-wheel rim; uneven poise creates rate error that changes with orientation |
| Pivot eccentricity | the unavoidable slight off-centre seating of a staff in its jewel hole; the root cause of positional error |
| Poising tool | the small instrument used to check and correct balance-wheel poise by rotating it on its own staff between parallel rails |
