Pictured: Datograph Perpetual Tourbillon by A. Lange & Söhne, Photo Courtesy of A. Lange & Söhne

You’ve taken the plunge and bought a new watch with all the bells and whistles. But before you start making adjustments, you might want to check the handling precautions, particularly for complications. These tiny mechanical marvels need special care or you may find it hard to convince the watchmaker that you didn’t contribute to the problem when something goes wrong.

The fact is, these timepieces do not react well to certain operations, and some adjustments must not be made at certain times. Here’s a few tips to avoid the most common problems for calendar watches.

Perpetual calendars

I am fascinated by perpetual calendars because they track time on so many different levels—seconds, minutes, hours, days, weeks and years, usually with a moonphase thrown in. But they are prone to handling errors, mainly to do with the timing of making calendar adjustments. The problem is that it takes a lot of mechanical energy for these indications to work, relative to the watch’s scale. Numerous cams and gears keep track of the indications, and they must be engaged gradually over the course of several hours to make efficient use of the mechanical energy of the timepiece.

So the challenge is to remember at which times adjustments can be made to the indications on your perpetual calendar. Midday seems to be the most common “safe zone.” You can set the time—always forward—to noon and make the adjustments. Just remember to set the watch to the day before, then slowly advance the time to the next day until the correct time is shown.

For perpetual calendars that do not have pushers to adjust individual indications, but are linked and adjusted via the crown, you generally cannot turn the time backwards. So the calendar adjustment must be made slowly so that you don’t turn the calendar indications too far forward. Stories abound of those who have continued to move the calendar forward, believing it will revert to the beginning like a date display—and who eventually have to send the watch to the service centre to be reset. 

Date displays

Even a simple date display is subject to adjustment constraints. You should avoid changing the date on a mechanical watch between 10pm and 2am as the gears are already engaged to make the date disc rotate near midnight. Unless your manual says otherwise, never turn the time back on a watch with a time display before midnight, as you could damage the date-changing mechanism.

So if you want to avoid handling mishaps, it’s a good idea to check the manual for instructions specific to your watch. Some watchmakers have tried to address this issue by developing more user-friendly mechanisms. But don’t take it for granted—a few years ago I asked the watchmaker behind a well-known perpetual calendar module how he remembered the instructions, especially when crossing time zones. He said he couldn’t, so he didn’t bother adjusting his watch when
he travelled.

This article was published in the December edition of Hong Kong Tatler.