How a mechanical watch works



Watches featuring a mechanical movement, both manual and automatic, are an icon of style and history that never gets old. Over the years, some watches have become true symbols of the art of watchmaking, design, and mechanics, capable of telling the story of the era in which they were designed and manufactured.

The charm of a mechanical watch, of the functioning of its components, is difficult to achieve by other accessories.

In the following paragraphs we will examine how these movements work and the technical differences from quartz movements.

Manual winding mechanical movements

The movement of a mechanical caliber originates from the elastic force generated by a spiral-shaped spring, positioned inside a toothed cylinder (the “barrel”) that allows the spring to extend by turning in one direction (supplying the necessary energy in a controlled way), while turning in the opposite direction, once discharged, it recompresses the spiral, thanks to the winding process activated by the crown.

The mainspring is one of the essential components of a mechanical movement and has been subject to studies over the years in order to improve its performance. 

Initially, they were produced in carbon steel alloy, but they were subject to corrosion and damage ending to compromise the reliability of the watch. Therefore, different alloys with nickel, cobalt, and other materials replaced it.

The spring, by releasing energy, originates the rotation of the wheel train, composed of gears and pinions with teeth whose dimensions and quantities are calculated with extreme precision. 

The main wheels, which are always present, are the center wheel, the intermediate wheel, the hours-minutes-seconds wheels and the escapement wheel.

These are usually made of brass and they are held in position by bridges where we find rubies, lubricated to ensure that the pins would turn with the least possible friction in order to minimize energy dissipation.

What allows the watch to mark time is the escapement, receiving energy from the barrel’s spring and, through the escapement wheel, transmitting it to the anchor, releasing energy in a constant way, oscillating thanks to the balance wheel that has the duty of regulating the speed.

The escapement wheel can be of different types: crown, anchor, cylinder, coaxial or tourbillon (one of the most complex).

The movement of the anchor is calculated in alternations, that is half of an oscillation, generally are 28’800 per hour but there are models with different frequencies. A high number of alternations allows the watch to be more precise.

The anchor generally consists of an input lever and an output lever, as well as a stem that oscillates in a delimited space with extreme precision.

The balance wheel, responsible for giving the pace to the rate is considered the “heart” of the movement, consisting of a circular wheel, usually with three radii, and a spiral spring which allows the oscillations.

One of the fundamental components of the balance wheel is the plateau, which transforms the movement of the gear wheels into oscillation and unites the anchor and the balance wheel.

Initially the spring was wound with a special key at least twice a day. Today it is possible to wind it through the crown, taking care not to exaggerate with the turns in order not to damage the spring, which however has protections that avoid damages.

The power reserve of a watch, usually around 37 to 44 hours depending on the type of movement, does not depend only on the spring but on the whole movement.

Some watch brands have tested movements with two barrels to increase the autonomy of the timepiece, reaching over 70 hours or even a week in extremely particular and refined models.

Self-winding mechanical movements

The operating principle of a self-winding movement follows that of the mechanical watch with manual winding, except for the process of winding the watch that (in addition to turning the crown) takes place through the oscillating mass (or rotor) mounted on a module that connects it to the gearing: the movement of the wrist cause the oscillation of the rotor that actuates the winding of the spring inside the barrel. It is always possible to use the crown, but this system allows you to always have the watch wound, simply by wearing it.

Quartz movements

Quartz movement is a technological innovation born in the last decades, initially in Japan and then exported all over the world. Again, to set the movement in motion an energy source is required. In this case energy comes from a battery which generates electrical charges that exploit the reverse piezoelectric physical properties of quartz. 

A very thin slab of quartz receives electrical impulses and vibrates at a frequency of 32’768 hertz/sec.: in this way it produces and transmits energy to a magnetic wheel connected to the gearing. 

Thanks to this high frequency, quartz watches are more accurate than mechanical ones and much cheaper.