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Watch Components

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Term Definition

Another word for plastic. In vintage or lower-value watches, this is the clear covering over the watch face; more expensive watches today tend to use sapphire instead. Sapphire is scratch-resistant; but its very hardness also makes it more prone to shattering.


Balance Spring
Acts like the pendulum of a watch. It is the concentric ring of metal in an escapement that extends and contracts at regular intervals. To achieve ultimate precision, the spring needs to achieve perfect isochronism. Simply put, the expansion and contraction of the balance spring needs to occur at a highly precise rate, with perfect all-round geometry, regardless of the position of the watch.


The energy source of a mechanical watch. It is a flat, cylindrical housing that has a tiny spring inside known as the ‘mainspring’, which coils up and accumulates enegery when one winds up the watch.


Winding a watch gives it energy by coiling up the mainspring. Left on its own, this energy would be spent in an instant as the mainspring unspools. The escapement is that part of the movement that takes this stream of energy and releases it in discrete bursts, to drive the balance wheel. 



A very fine spiral spring attached to the watch’s balance wheel. Its responsibility is to help the balance wheel oscillate at a pace at determines the timepiece’s precision. Think of it loosely as the wristwatch version of the string attached to a pendulum of a grandfather’s clock, which helps facilitates the tick-tocking of the clock.

Jewel (Movement)

Or ‘jewel bearing’. It sounds like a lavish component, but a jewel in a modern wrist watch is a synthetic ruby or sapphire that acts as a bearing to mininmise wear-and-tear caused by friction between metal parts. They are typical purple and donut-shaped, and you can identity them easily from an open case back.


The bits of metal that protrudes the either ends of a case that hold the watch strap or bracelet in place.



Not as ominous as you imagine it to be. A pusher is a component that works like a button to activate additional watch mechanisms, such as the chronograph counter. Also commonly known as ‘push-button’.