What is a hairspring in a watch?

Vaer Watches Updated by Vaer Watches

A hairspring, also known as a balance spring, is a thin, coiled spring in a mechanical watch that is used to regulate the movement of the watch's balance wheel.

The hairspring is typically made of a thin strip of metal, such as an alloy of steel, titanium, or silicon, that is coiled into a spiral shape.

The hairspring is attached to the balance wheel and acts as a type of torsion spring, resisting the motion of the balance wheel as it oscillates back and forth. This resistance causes the balance wheel to oscillate at a consistent rate, which in turn regulates the movement of the watch's gears and hands.

The rate at which the balance wheel oscillates is determined by several factors, including the length and thickness of the hairspring, as well as the mass of the balance wheel. Small adjustments to the length or thickness of the hairspring can have a significant impact on the rate of oscillation, and therefore on the accuracy of the watch's timekeeping.

The hairspring is a critical component of a mechanical watch movement, and it must be manufactured to extremely high standards of precision to ensure that it functions properly. Any damage or deformation to the hairspring can cause the watch to run too fast or too slow, and can require delicate and precise adjustments to be made by a trained watchmaker.

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