Expertise

'Caliber' is an expression used in the watch industry to describe a particular movement. It is a synonym for 'dimension' or 'size'. In the art of watchmaking, this term includes the order and dimensions of the individual parts, the spindles, wheels and the mainspring barrel. In the course of time the meaning of the technical term 'caliber' has been extended. Today it includes the shape of a movement and its bridges along with its origin and the name of the manufacturer. For example; if we were to speak of an 'ETA Cal. 2412' or 'AS Cal. 1130' movement, an experienced watch enthusiast or watchmaker would know which movement we mean. He would recognise the size of the movement expressed in 'lines', which is a unit of measurement used only in watchmaking. This brings us back to the original use of the expression 'caliber'. Watches that have the same calibre, for example, 6¾ x 8 (lines), have the same dimensions – even when made by different manufacturers.

A unit of measurement for gold alloys. In a 1-carat alloy, pure gold will make up one twenty-fourth (1/24) of the total weight. Consequently, 12- carat gold, has twelve twenty-fourths (12/24) pure gold content; 24-carat gold is pure gold.

This is a striking mechanism with at least three different tones. The Carillon marks the hours with a deep tone, the minutes in a high tone and the quarter-hours in a chord of three tones.

A wristwatch with additional stopwatch functions (Greek: chronos = 'time' and grapho = 'I write'). The chronograph has hour, minute and second displays and a control mechanism for the chronograph functions. The dials are started, stopped and reset by pressing pusher buttons near the crown. One revolution of the chronograph dial takes one minute. A separate 'recorder' dial records the number of revolutions (minutes) to a maximum of 30 minutes.

See Double Chronograph.

Only exceptionally precise watches whose accuracy is certified by a recognised institute of time measurement are permitted to carry the distinction of being called chronometers. In Switzerland, these certifications are carried out by the COSC (Contrôle officiel suisse des chronomètres). Following tests, which take approximately two weeks, this institute verifies the accuracy of a watch by awarding a 'bulletin officiel de marche' certificate of accuracy.

A classic type of Chronograph in which the start, stop and reset functions are controlled through a device called a 'column wheel'. The finishing of this mechanism calls for some very demanding handwork, which is why it is rarely used today. Watches with this mechanism from the 30's and 40's, a time when it was more popular, are much coveted by collectors.

Complications are watches that can do more than display the time in hours, minutes and seconds. A chronograph, for instance, is a 'Complication'. A watch described as a 'Great or Grande Complication' could include a striking mechanism, a repetition, an eternal calendar or some other complex features.

See Chronometer.

Finishing work on high value watches in which plates and bridges are finished off with rounded stripes. Also known as 'Geneva stripes' or 'Geneva finish'.