Episode · The watch, explained
Inside a watch.
And why some cost so much.
A mechanical watch is a small machine that stores energy, lets it out in equal beats and turns those beats into the time. Choose any part of the drawing to see what it does, follow the energy from spring to hands, then read the honest reasons a few of these machines become luxury objects.
01 / Piece by piece
The watch, taken apart
An original drawing of an automatic watch, opened layer by layer from the crystal to the strap. Choose a part in the drawing or in the list.
The clear cover over the dial. Most fine watches use synthetic sapphire, so hard that in everyday life only diamond scratches it easily. Many older watches use acrylic, which scratches more readily but can be polished.
The ring that holds the crystal in place. On a diver’s watch it turns in one direction only, so the time underwater can be read against the minute hand. On a travel watch it can carry a 24-hour scale for a second time zone.
Hour, minute and often seconds hands, sometimes filled with luminous material for the dark. In fine watches they are cut, shaped and polished with great care, because they are the parts you look at most.
The face of the watch. It can be lacquer, enamel, stone, engraved metal or a fine engine-turned pattern, with printed or applied hour markers. The dial carries much of a watch’s character.
The half-moon weight of an automatic watch. It swings as the wrist moves and winds the mainspring. A hand-wound watch has no rotor: it is wound by turning the crown.
The engine of the watch: the mechanism that stores energy, releases it in equal beats and turns those beats into hours, minutes and seconds. A simple automatic movement has well over a hundred parts.
The case protects the movement from dust, water and knocks. It is usually steel, gold, platinum, titanium or ceramic. The crown, on the side, winds the watch and sets the time; a screw-down crown helps keep water out.
Closes the case from below. A clear sapphire back shows the movement and its decoration. A solid back can carry an engraving, and on some watches hides a soft-iron shield that protects the movement from magnetism.
Leather, rubber, fabric or a metal bracelet with links and a clasp. Many bracelets now have a small adjustment in the clasp, so the fit can change during a warm day.
02 / From power to time
How the energy travels
Every mechanical watch, simple or grand, follows the same five steps. The drawing moves slowly here; a real balance beats several times a second.
The mainspring stores the energy
A long ribbon of special alloy is wound tight inside a small drum called the barrel. As it slowly unwinds, it turns the barrel. The energy it holds is the power reserve: about two to three days in many modern watches, and five days or more in some.
The gear train passes it on
A chain of wheels turns the barrel’s slow movement into faster turns. In a typical layout one wheel turns once an hour to carry the minute hand, and another turns once a minute for the seconds.
The escapement lets it out in steps
Left alone, the spring would spin the wheels in seconds. The escapement, an escape wheel and a small rocking lever called the pallet fork, lets the train move on one tooth at a time and gives the balance a tiny push at each step. That is the tick you hear.
The balance keeps the beat
The heart of the watch. The balance wheel swings back and forth, returned each time by a hairspring finer than a hair. Each swing takes the same time, so the balance is the watch’s measure of time. Many modern watches beat 28,800 times an hour, or 4 hertz.
The hands show the time
Under the dial, a small set of wheels makes the hour hand turn twelve times slower than the minute hand. The steady beats of the balance have become hours, minutes and seconds.
03 / A fair comparison
Mechanical or quartz?
Quartz
A battery makes a tiny quartz crystal vibrate 32,768 times a second, and a circuit counts the vibrations. It is usually far more accurate, cheaper to make and needs little care.
Mechanical
A wound spring and a swinging balance, with no battery at all. A good one is accurate to a few seconds a day. It can be opened, repaired and adjusted by hand for generations, and you can watch it work.
So a mechanical watch is not chosen for accuracy. It is chosen for the craft inside it and for how long it can last.
04 / More than the time
Complications, simply explained
Watchmakers call any function beyond hours, minutes and seconds a complication. Each one adds wheels, levers and springs to the movement.
- Date
- Shows the date through a small window, and changes it at about midnight.
- GMT or dual time
- An extra hand on a 24-hour scale shows the time in a second time zone.
- Chronograph
- A stopwatch built into the watch, started, stopped and reset with pushers on the side.
- Moon phase
- A turning disc follows the moon’s cycle of about 29 and a half days.
- Annual calendar
- Knows which months have 30 or 31 days, so it needs correcting only once a year, at the end of February.
- Perpetual calendar
- Also knows February and leap years. In principle it needs no correction until 2100, a year that is not a leap year.
- Tourbillon
- The escapement and balance turn inside a small rotating cage, to even out the effect of gravity. Abraham-Louis Breguet patented it in 1801.
- Minute repeater
- At the press of a slide, tiny hammers strike gongs to chime the hours, quarter hours and minutes.
05 / The real question
Why some watches are luxury
A phone tells the time more accurately for much less. A luxury watch is valued for something else: the time, skill and materials that went into it, and how long it will last. Eight reasons explain most of the price.
Hours of hand finishing
In fine watchmaking, the edges of the bridges are bevelled and polished by hand, flat surfaces are decorated with fine stripes or overlapping circles, and small steel parts are polished until they flash dark or bright in the light. One hand-bevelled bridge can take hours, and most of this work is hidden once the case is closed.
Precision made by people
Parts are made to within a few thousandths of a millimetre, then assembled, oiled and adjusted by watchmakers. A complicated watch can be put together by one person over many weeks.
Precious and difficult materials
Gold and platinum cases, sapphire crystals, ceramic bezels and special alloys for hairsprings that resist magnetism and changes in temperature. Platinum, for example, is dense and hard to machine.
Complications
Every extra function adds parts, years of design and hours of assembly. Vacheron Constantin’s Reference 57260, shown in 2015, gathers 57 complications and took about eight years to make.
Proven precision
Certificates add testing time and cost. Chronometer certification tests a movement for 15 days, in five positions and at three temperatures, for an average rate between −4 and +6 seconds a day. Master Chronometer testing goes further on the finished watch, including a magnetic field of 15,000 gauss. The Geneva Seal, created in 1886, also asks for the watch to be assembled in Geneva and finished to set rules.
Small numbers
Some models are made in hundreds, not millions. Limited editions and waiting lists make them scarce, and scarcity raises prices.
Made to be repaired and kept
A mechanical watch is designed to be serviced: taken apart, cleaned, oiled and adjusted every few years. Well kept, it can run for generations, which is why many families hand watches down.
Name, history and design
Houses with long histories and recognisable designs carry a reputation that buyers value. To be honest, part of a luxury price also pays for the brand, advertising, shops and demand, not only for the parts and the work.
The honest answer: a luxury watch is expensive because of the hours, the materials, the testing and the scarcity, and partly because of its name. None of that makes it tell the time better than a phone. It makes it something made by people, to be kept.
Questions readers ask
How many parts are in a mechanical watch?
A simple automatic watch has well over a hundred parts. Grand complications, with chimes and calendars, can have more than a thousand.
What is the movement of a watch?
The movement is the mechanism inside the case: the mainspring that stores energy, the gear train, the escapement, the balance that keeps the beat and the wheels that turn the hands.
Are mechanical watches more accurate than quartz watches?
No. A quartz watch counts the vibrations of a tiny quartz crystal, 32,768 times a second, and is usually far more accurate. A good mechanical watch is typically accurate to a few seconds a day. People choose it for its craft and its life span, not for precision.
Why are luxury watches so expensive?
Mostly because of hand finishing, precise hand assembly, precious materials, complications, testing and small production numbers. Part of the price also reflects the brand, shops and demand.
What do the jewels in a watch do?
They are synthetic rubies used as hard, smooth bearings where the steel pivots of the wheels turn. They reduce friction and wear. A simple watch has around 17 to 25; more jewels do not by themselves mean a better watch.
How often should a mechanical watch be serviced?
Most makers advise a service every five to ten years. The maker’s own advice for your model is the best guide.
Keep exploring
This month’s new watches Compare watches side by side The history of timekeeping The watch houses
Sources
- Fondation Haute Horlogerie, Horopedia: Certification of chronometers according to ISO 3159
- Fondation Haute Horlogerie, Horopedia: The Geneva Seal
- OMEGA: The Master Chronometer certification
- Breguet: The tourbillons of the inventor
- Vacheron Constantin: Reference 57260
Figures for certification are the published criteria of each programme. Drawings are original illustrations for this website.