How Swiss Watches Are Made

From raw brass to finished movement — the production process inside a Swiss watch manufacture.

A mechanical Swiss watch contains between 100 and 400 individually machined components. They fit inside a case the diameter of a coin, operate continuously without external power, and are expected to keep accurate time for decades.

This piece follows the production process from raw material to finished watch.

The movement: where it begins

The movement is the engine of the watch. It converts the stored energy of a wound spring into the regulated oscillations of a balance wheel, which in turn drives the gear train that moves the hands.

At the centre of every mechanical movement is the mainspring — a thin strip of steel alloy coiled inside a barrel. When wound, the mainspring stores potential energy. As it unwinds, it releases energy through the gear train at a rate controlled by the escapement and balance wheel.

The movement plate and bridges — the structural frame that holds all components — are machined from brass alloy. Brass machines cleanly, resists corrosion, and can be plated in rhodium, gold, or nickel. In high-grade movements, the plate is made from German silver, a brass-copper-nickel alloy that takes finishing better than standard brass.

Machining: precision at the micron level

Movement components are machined by CNC (computer numerical control) equipment to tolerances measured in microns. One micron is one thousandth of a millimetre. A human hair is approximately 70 microns in diameter. The tolerances in a high-grade watch movement are a fraction of that.

"A movement assembled by hand takes three to four times longer than one assembled by machine. We do it because the tolerances we work to are not achievable any other way at that scale. There is no philosophical reason. It is purely technical." Corinne Bärtschi, movement assembly supervisor, Vallée de Joux

The gear wheels that transmit power through the movement are cut with profiles precise enough that microscopic imperfections in the tooth form would be audible as a change in the movement's sound. The quality of a movement's gear cutting is one of the first things an experienced watchmaker assesses.

Jewels — synthetic ruby bearings — are pressed into the movement plate at pivot points where rotating shafts contact the plate. Jewels reduce friction at these points. A standard automatic movement contains 25 jewels. More complex movements contain more.

Finishing: the human step

After machining, components pass to finishing — a stage that cannot be automated and distinguishes high-grade from standard production.

Côtes de Genève — Geneva stripes — are applied to bridges and plates using a rotating zinc plate loaded with abrasive. Manufactures like IWC Schaffhausen have built their reputation in part on the consistency of this finishing work. The craftsperson moves the component across the plate in a series of parallel strokes, producing an even striped pattern. One bridge may take 20 minutes of careful work.

Anglage — bevelling — is applied to the edges of every component. A trained finisher uses a hand file or polishing stick to create a precise 45-degree chamfer on every edge. The chamfer is then polished to a mirror finish using a Rodico stick loaded with polishing compound. On a single bridge, there may be 40 individual edges requiring anglage. Each one takes approximately two minutes.

Screw heads — the visible fasteners that hold bridges to the plate — are turned on a lathe after threading, then polished to a mirror finish by hand. A finished screw head reflects light as a perfect circle. An unfinished one does not.

Assembly: the watchmaker's role

Movement assembly is performed by trained watchmakers under magnification, using tweezers and screwdrivers. The process is sequential. Components must be installed in a specific order, with springs tensioned at the correct stage to avoid damage.

The balance wheel and escapement are the last components installed. The balance wheel — the oscillating heart of the movement — rotates back and forth at a frequency of 2.5 to 5 Hertz, depending on the calibre. Each oscillation allows one tooth of the escape wheel to advance, advancing the gear train by one increment.

At a frequency of 4Hz (28,800 vibrations per hour), the balance wheel completes 345,600 oscillations every 24 hours. Over a year, it oscillates approximately 126 million times. The mechanical system that sustains this motion, without external power, is what a trained watchmaker assembles in a day's work.

One of us in the SwissMastery team held an unfinished movement blank next to a completed and finished version of the same calibre during a factory visit in Le Locle. The transformation is significant. The finished piece reflects light differently from every angle. The unfinished one looks like industrial hardware. Both keep exactly the same time. The finishing adds nothing to the function and everything to the reason you want to own it.

Regulation and certification

After assembly, the movement is regulated. A watchmaker measures the movement's daily rate across multiple positions — dial up, dial down, crown up, crown down, crown left, crown right — and adjusts the regulator to bring the rate within tolerance.

COSC (Contrôle Officiel Suisse des Chronomètres) certification requires a daily rate between minus 4 and plus 6 seconds across 16 days of testing. Movements that pass receive a chronometer certificate. Many Swiss movements exceed this standard without formal certification.

Some brands apply additional proprietary certifications. Omega's Master Chronometer standard, tested by the Swiss Federal Institute of Metrology (METAS), adds magnetic resistance testing up to 15,000 gauss and water resistance verification. Patek Philippe's own seal sets even stricter rate tolerances and requires a 24-hour power reserve test.

Casing and final assembly

Once the movement passes regulation, it is cased. The movement is seated into the case, the crown stem connected to the winding and setting mechanism, and the caseback sealed. Water resistance testing follows. Pressure tests confirm that the gaskets hold to the stated depth rating.

The dial is fitted — a separate component, attached to the movement by dial feet — and the hands are pressed onto their respective shafts under a hand press that applies precise, controlled force. Too much force distorts the hand. Too little leaves it loose.

The watch is then worn on a timing machine for a final rate measurement before leaving the manufacture.

The standard behind the process

Every stage described above is governed by centuries of accumulated knowledge and institutional discipline. The Swiss watch industry does not produce watches the way it does because it has no alternative. It produces them this way because the standard demands it.

That standard — precise, disciplined, uncompromising — is the same one we apply at SwissMastery across every category we curate. For context on the brands that apply this process at the highest level, see Best Swiss watch brands (2026). For the cultural and commercial significance of the Swiss Made designation, see Why Swiss Made still matters.

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