Do not change the date on an automatic watch when the hands are between roughly 9 pm and 3 am. During those hours the date-change mechanism is already engaged, and forcing the date with the crown can bend or break a tooth. Set the hands to around 6 o'clock first, change the date, then set the time. Few people know why the rule exists — and once you understand the mechanism, you remember it for good and can adapt it to your own watch.
Does your watch change date at noon instead of midnight?
This is the most common case, and the watch is not broken. A dial only shows twelve hours: if the time was set on the wrong side of midnight, the watch "thinks" it is morning when it is evening. The result: the date flips around noon, or does not move at midnight.
The fix takes a minute: pull the crown out to the time-setting position and turn the hands through one full revolution of the dial (twelve hours). The date will advance by one day as the hands pass midnight; then correct it using the sequence below, outside the danger zone.
If the date has not changed at all for several days, the cause is simpler: the watch has stopped because it was not worn. Wind it, then set the time and date.
Why there is a danger zone
On a mechanical watch, the date change is not instantaneous: it is prepared over several hours.
A wheel driven by the movement gradually engages the date disc. The process usually begins in the evening and ends shortly after midnight. Throughout this phase, the teeth are engaged and under tension.
If you force the date change with the crown while this train is engaged, you push against a mechanism that is already under load. At best, nothing happens. At worst, a tooth bends or breaks — and that means a trip to the watchmaker for an adjustment that could have waited three hours.
Finding the danger zone on your watch
The 9 pm – 3 am window quoted everywhere is a wide safety margin. The actual window varies from calibre to calibre.
To find it: set the hands to around 10 pm and watch the date window. If the disc has already started to move, even slightly, the train is engaged. Keep advancing the hands until the date changes completely, then note the time at which the disc becomes perfectly still again.
That is your window. Outside it, there is no risk.
Some watches have a so-called instantaneous date change, where the disc jumps in a fraction of a second at midnight. The constraint remains, but the window is much narrower. If in doubt, apply the wide rule.
The safe sequence for setting the date
Always in this order.
1. If the watch has stopped, wind it a little — about twenty turns of the crown is enough to give it energy.
2. Move the hands outside the danger zone. Six o'clock in the morning is a safe position on every calibre.
3. Set the date, one crown position back.
4. Return to time-setting and bring the hands to the actual time, passing through midnight if it is the afternoon — that is what distinguishes morning from afternoon on a twelve-hour dial.
5. Push the crown fully home, and screw it down if your watch has a screw-down crown. It is the step people forget, and the one that costs the most.
Short months and February
Without an annual or perpetual calendar complication, your watch counts thirty-one days in every month. It will therefore be one day ahead after each thirty-day month, and three after February.
That means five corrections a year: on 1 May, 1 July, 1 October, 1 December and 1 March. The March correction is the biggest.
Never having to do it again
All this handling comes from a single cause: the watch has stopped.
An automatic worn every day does not have this problem. It appears as soon as you alternate between several pieces — the one you have not worn for three days has stopped, and everything has to be reset. Check your watch's power reserve to see how long it lasts off the wrist.
That is exactly what a watch winder solves: the watch stays wound and on time, and you pick it up without setting anything. It still has to turn in the right direction and at the right rate, which depend on your calibre: we publish the settings for 38 movements, whether you bought from us or not.