Antique Clocks

How to set the calendar dial of your clock

Many antique clocks have a calendar feature to show the current monthly date. This may be in the form of a small square box in the dial with a number showing through it, or a small crescent-shaped cutout in the dial showing the actual day plus a day or two each side of it, or a pointer. On most clocks the calendar is positioned just above the VI hour numeral. The manner of re-setting the date is the same, whichever form of calendar it has. It is not necessary to wind the main clock hands forward for days on end to re-set the calendar; in fact this is positively unwise.

Calendars are moved on by one full unit per day, but with some clocks (principally thirty-hour clocks) this may take the form of being moved half a turn twice a day. In other words the calendar changes by being moved one full unit every twenty-four hours, or one half unit every twelve hours. The calendar is 'in drive' (i.e. actually turning) for a period of three hours or so a day on a twenty-four-hour-changing calendar, and during this time it cannot be re-set. In the case of a twelve-hourly-changing calendar, it is 'in drive' during a period of three hours or so twice a day, and cannot be moved when 'in drive'.

The calendar, whether shown by a pointer or a disc, can be moved in the direction of ascending numbers when not in drive - this is usually clockwise but not always. Many calendars have a ratchet to stop them being moved backwards, and it is always safest to try to move them in order of ascending numbers. If the hand (or disc) refuses to move, let the clock run on for two or three hours more, and try again, as it should then be free to move. A pointer can be moved from the front, as with any clock hand. A disc calendar is better moved by sliding it from behind the dial.

It is not necessary to stop the clock from running when changing the calendar setting.

If the calendar does not progress as the clock runs, then the calendar drive is probably damaged or missing, and needs the attention of a restorer.

Copyright © 2013 Brian Loomes