Today’s mechanical wristwatches mostly use movements, or calibers, with automatic or manual wind. Electric motors or magnets are only rarely used. But who invented the mechanical watch? And how do mechanical watches work? This and other questions are answered in this article…

Who invented the mechanical watch?

In the 14th century, around the time of the development of the hourglass, the first wheel clocks were created. They were still very inaccurate, but already had a rest, the predecessor of the balance wheel. The individual parts of such wheel clocks were primarily made of forged iron. The wheel clock was used, for example, by tower guards to indicate the correct time for the bells to strike.

Already in the 15th century, the use of balance and spiral spring led to ever more precise movements. The watches of this time had to be wound with small keys, which were readily lost. Just 300 years later, Abraham Louis Perrelet solved this problem with an automatic winding for pocket watches. Later, in 1838, the company Audemars introduced the first pocket watch with crown winding.

Can watches from Peter Henlein as a forerunner of pocket watches

Nuremberg master locksmith Peter Henlein was the first German to succeed in producing a watch that could be worn on the body. Around 1479 he created the forerunner of later pocket watches. For his watch creations, Henlein preferred shapes such as tall cylindrical cans or small pomegranate balls, which is why they were also referred to as “can watches”. Unlike the later pocket watches, Henlein’s can watches were worn in small bags on the body and not on chains around the neck.

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Photo: Steffi Tremp, Räderuhr, CC BY-SA 3.0

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Photo: Vitold Muratov, Dosenförmige tragbare Uhr, CC BY-SA 3.0

The first mechanical wristwatch

The first wristwatch, with credible evidence, was made by Abraham Louis Brequet, a Swiss watchmaker, around 1810 for Napoleon’s youngest sister, Caroline Bonaparte. Until the invention of the automatic wristwatch, it still took more than 100 years from then on.

Most of the mechanical movements installed today have their design origins in the 1960s and 1970s. Until shortly before the quartz crisis, many new calibers were developed, including, for example, two chronograph movements presented in 1969, which worked for the first time with automatic winding: the El Primero from Zenith and the Caliber 11. In order to be able to finance the investment for the Caliber 11, the industry giants Heuer, Breitling, Buren Watch SA, Dubois-Dépraz SA and later also Hamilton teamed up. The Caliber 11 was wound via a barely recognizable microrotor.

How do mechanical watches work?

The energy for driving mechanical movements comes from the winding stem. It is wound on hand-wound watches by turning the crown and, in the case of automatic watches, over a ball-bearing rotor. The motion of the watch when moving the arm cause the rotor to pivot on its staff thereby winding an s-shaped mainspring. In automatic movements, this spring is typically wound in both directions of rotation. A slipping clutch prevents over-tightening of the mainspring. The spring stores the energy and is housed in the mainspring barrel. When the spring relaxes over time, the barrel is turned, which causes all other wheels in the gear train to turn.

The escapement allows the watch’s uncontrolled course of the gear train to advance or “escape” by a fixed amount, converting the transmitted rotational energy into a periodic cycle. This cycle is regulated by the balance wheel. Finally, the movement of the gear train is transmitted to the hands and so the time is displayed on the dial.

Care, revision and cleaning of a mechanical watch

Most high-quality mechanical movements use synthetic gems like rubies as bearing for moving parts. There is less friction between stone and steel than between two steel components, which reduces wear and increases accuracy. However, friction can never be completely avoided and even the finest dirt particles that have penetrated the watch can contribute to the wear and tear of lubricants and materials. Extreme temperatures can accelerate this wear as well and should therefore be avoided, just like magnetic fields, that can damage the many fine, moving parts.

There is no fixed revision interval, since it depends very much on personal wearing behavior and, of course, on the movement itself, how often a revision is due. As a rule of thumb, you can say that a mechanical watch has to be revised every 3 to 7 years – here the watchmaker disassembles and cleans the complete movement before it is reassembled and oiled.