Monday, August 29, 2005


Precious stone used in movements as a bearing surface. Generally speaking, the steel pivots (s.) of wheels in movements turn inside synthetic jewels (mostly rubies) lubricated with a drop of oil. The jewel’s hardness reduces wear to a minimum even over long periods of time (50 to 100 years). The quality of watches is determined mainly by the shape and finishing of jewels rather than by their number (the most refined jewels have rounded holes and walls to greatly reduce the contact between pivot and stone).

Feature concerning the digital display of time in a window. The indication changes almost instantaneously at every hour.

Ancient French measuring unit maintained in horology to indicate the diameter of a movement (s.). A line equals 2.255mm. Lines are not divided into decimals; therefore, to indicate measures inferior to the unit, fractions are used.

To reduce friction caused by the running of wheels and other parts. There are points to be lubricated with specific low-density oils such as the pivots (s.) turning inside jewels (s.), the sliding areas between levers, and the spring inside the barrel (requiring a special grease), as well as numerous other parts of a movement.

Double extension of the case middle (s.) by which a strap or bracelet is attached. Normally, straps and bracelets are attached with removable spring bars.

Said of materials applied on markers (s.) and/or hands (s.), emitting the luminous energy previously absorbed as electromagnetic light rays. Tritium is no longer used and was replaced by other substances having the same emitting powers, but with virtually zero radioactivity, such as Super-LumiNova and Lumibrite.

This and the barrel (s.) make up the driving element of a movement (s.). It stores and transmits the power force needed for its functioning.

A mechanical movement (v.) in which winding is performed by hand. The motion transmitted from the user’s fingers to the crown is forwarded to the movement through the winding stem (s.), from this to the barrel (s.) through a series of gears (s.) and finally to the mainspring (s.).

Elements printed or applied on the dial, sometimes they are luminescent (s.), used as reference points for the hands to indicate hours and fifteen- or five-minute intervals.

Element positioned on the regulator, allowing to shift it by minimal and perfectly gauged ranges so as to obtain accurate regulations of the movement.

MICRO-ROTOR, s. Rotor.


Self-contained mechanism, independent of the basic caliber (s.), added to the movement (s.) to make an additional function available: chronograph (s.), power reserve (s.), GMT (s.), perpetual or full calendar (s).

A function available in many watches, usually combined with calendar-related features. The moonphase disc advances one tooth every 24 hours. Normally, this wheel has 59 teeth and assures an almost perfect synchronization with the lunation period, i.e. 29.53 days (in fact, the disc shows the moonphases twice during a single revolution). However, the difference of 0.03 days, i.e. 44 minutes each month, implies the need for a manual adjustment every two and a half years to recover one day lost with respect to the real state of moonphase. In some rare case, the transmission ratio between the gears controlling the moonphase are calculated with extreme accuracy so as to require manual correction only once in 100 years.

The entire mechanism of a watch. Movements are divided into two great families: quartz and mechanical; the latter are available with manual (s.) or automatic (s.) winding devices.

Trade name (from the producer’s name) of a steel alloy, resisting magnetization, used for modern self-compensating balance springs (s.). The quality level of this material is indicated by the numeral following the name in decreasing value from 1 to 5.

Complete oscillation or rotation movement of the balance (s.), formed by two vibrations (s.).