Watchmaking glossary

Watchmaking glossary – Illustrated and comprehensive watchmaking dictionary

Here you will find a glossary explaining certain watchmaking terms. The goal is not to be exhaustive, there are specialized professional sites for this. Here we have selected the terms that you are likely to encounter in your watch research when you compare models for purchase when you read a slightly more technical article, or simply if you want to know more. We also wanted to make this glossary more complete and pleasant to read, several terms are commented on and illustrated with photos.

This glossary is evolving, do not hesitate to ask us for additional information or terms not currently included.

Glossary

Cellulose acetate

This is the material from which many high-end eyewear models are made. And it has become the hallmark of Briston, a French watch brand known for its square-shaped watches. Made from cotton fibers and flowers (70%), it is a natural and hypoallergenic material.

Blued Steel

: Watch hands frequently have a blued appearance: this color is obtained by heating the needle, which causes the steel to oxidize and gives it a certain color. The color obtained depends on the temperature, blue is the most common color in watchmaking, but other colors are possible such as straw yellow, or gray.

316L steel

316L steel is a surgical grade stainless steel very frequently used for the manufacture of watch cases and crowns, but also for other parts such as bridges. Note that there are other qualities of steel, such as 904L, used by Rolex because it has greater resistance to corrosion.

Alternation

The alternation of a pendulum movement is the distance between two extreme positions of the pendulum, i.e. half of the round trip movement (called oscillation). In watchmaking, this term characterizes the sizing of the balance-spring couple. The escape wheel advances by one tooth at the rate of two alternations. In practice, you will often hear of movement at 21,600, 28,800, or 36,000 vibrations per hour Translated into Hertz, this gives

For 21,600 vph, this gives 6 vibrations per second or 3 oscillations per second: we then speak of a frequency of 3 Hz
For 28,800 vib/h, it is a frequency of 4 Hz
For 36,000 vib/h, it is a frequency of 5Hz

A higher alternation normally allows better precision of the watch. The ETA 2824 movement, widely used in mid-range watches, beats at 28,800 vph. Another example is Grand Seiko’s “20th-anniversary” caliber 9S85, referred to as “hi-beat”, with a frequency of 36,000 vph. By comparison, Bulova’s Accutron movement beat at 360 Hz.

Nonmagnetic or antimagnetic

The terms non-magnetic and anti-magnetic are synonymous. A watch caliber is most often made up of moving metal parts. This movement can be strongly disturbed when certain parts become magnetized. The proof is that a watchmaker will always demagnetize the caliber he is winding before adjusting it. To reduce this risk, the most sensitive parts (balance-spring, escapement, for example) can be made of non-magnetic metals or alloys. Another way is to protect the movement with a soft iron cage, as is the case with pilot watches. On older watches, this feature was often indicated on the back of the watch. This is less the case today.

The Anchor

: is a crucial part of a watch movement. Along with the escape wheel, it forms the organ for distributing the energy generated by the mainspring.

Antichocs

The anti-shock is a safety system that protects the balance shaft against shocks. The most common model is the Incabloc, but other systems exist the Etachoc (produced by ETA), the Kif system (Rolex), the Diashock (Seiko), or Parashock (Citizen).

The pin

: is the hinged piece of metal that enters the holes in a leather strap. A good tip, if you throw away an old used bracelet, always keep the buckle, especially if it is signed. It can still be used, and you would be surprised to see the prices of a simple buckle on the second-hand market.

Barrel

The barrel is the organ that houses the spring, which stores the energy that will make the watch turn. It consists of a drum, a cover, and a shaft around which the spring will wrap. On watches with alarms, there are generally two barrels: one store the energy used for the normal functions of the watch while the other stores the energy necessary for the implementation of the hammer which will generate the alarm.

The bar

The bars are used to attach the bracelet to the lugs of the watch. There are different types of barrettes, depending on the different types of horns.

Watch case

is simply designates the box that surrounds and protects the watch’s movement. It is typically made up of a crystal that protects the front face of the watch, a case back that protects the back face, and a middle part that actually constitutes the body of the watch.

The case gives the watch its general shape, the aspect that we remember at first glance. But the general appearance of the watch can also be directly influenced by the shape of the bezel, which is often circular. A good example is the Panerai Radiomir, whose cushion-shaped case and round bezel.

Accutron

is the trade name given by the American Bulova to its revolutionary watch mechanism based on the principle of resonance This principle had already been imagined by Breguet The “ACCUracy through ElecTRONic” system is the result of several years of research carried out in the 1950s and led to the production of the first tuning fork watch in 1960.

With a frequency of 360 Hz (instead of 4 to 6 Hz for a good classic mechanical watch), its precision crushes everything that was done at the time, with a drift of one minute per month. This is the Spaceview, it has no dial, and the inside of the watch is quite visible. There is no crown, the setting of the watch is done from the back. And the most beautiful thing about the story is the soft noise it emits: a slight rustle resembling a mosquito to some, a buzzing to others. In any case, I advise you not to put the watch on the bedside table before going to sleep!

Cabochon

In jewelry, a cabochon is a polished stone, but not cut into facets. In watchmaking, cabochons are sometimes used, for example, placed on the crown, as on this Seiko Brightz.

Dial watch

The watch dial is the visible part of the front face of the watch, it is the “face” of the watch. It is he who gives the information relating to the time. A dial is characterized as:

• by the material used,
• by surface treatment
• by the color(s)
• by the configuration of the elements that make it up (counters, windows, etc.)
• by the relief that it can present.

The middle part

is the part of the watch case, which forms the link between the crystal and the back.

Chronograph

A chronograph watch makes it possible to measure more or less long periods of time in a more or less precise way. In addition to the traditional hour, minute, and second hands, the chronograph also has at least two hands and one or two pushers. The Rolex Cosmograph Daytona and Omega Speedmaster chronographs are arguably the most publicized chronographs. For their part, Breitling and Heuer have built their reputation on the quality of their chronographs.

Stopwatch

A chronometer is a watch whose high precision is certified by tests carried out by an independent body. In Switzerland, this organization is the COSC (Swiss Official Chronometer Testing Institute).
Some brands like Breitling have all their movements certified by the COSC.

The lugs

are the part of the case used to attach the bracelet to the middle. They are generally placed at the top (at 11 a.m. and 1 a.m.) and at the bottom (at 7 a.m. and 7 a.m.). The bracelet is generally fixed with a bar that crosses the end of the bracelet and which is fixed in two small holes drilled on the inner faces of the lugs. When these small holes cross the horn, we will then use through bars. On older watches, the lugs sometimes have a pivot, which requires the use of suitable bars.

COSC

Founded in 1973 and based in La Chaux-de-Fonds, the Swiss Official Chronometer Testing Institute (COSC) is a non-profit association recognized as being of public utility, which works in the service of Swiss watchmaking. Created by five watchmaking cantons (Bern, Geneva, Neuchâtel, Solothurn, Vaud), as well as by the Federation of the Swiss Watch Industry (FH), the COSC brings together independent laboratories that have existed since the end of the 19th century.

The crown

or winding crown is the button placed on the side of the case middle and which is used on the one hand to set the time and, if applicable, the date and the day, and on the other hand to wind the spring of the barrel (for mechanical watches).

Date and day

The date is the simplest complication that can be found on a watch, along with the small seconds. The date, also called the calendar, is most often displayed in an aperture, but can also be indicated by a hand, sometimes retrograde as on the Longines. Watches displaying the date are sometimes called “Date” as at Rolex with the Datejust.

The problem with the date is that the months have 30 or 31 days and that the month of February has 28 days except in a leap year when it has 29. The date is therefore not that simple, and that makes l object of other complications such as the annual calendar and the perpetual calendar.

The day is the indication of the day of the week. Like the date, it is indicated in an aperture or with a hand. Often placed next to the date, it is sometimes separated from it. This type of display is called “Day-Date” as on this Rolex Day-Date 40 with a meteorite dial.

Until proven otherwise, there is no watch displaying the day without displaying the date.

Finally, note that the day is frequently offered in two languages: usually English, and another local language. This is how Japanese or Arabic is sometimes found on dials.

Let’s end with this Andersen Geneva Perpetual Secular Calendar “20th Anniversary” which offers us the days of the week in their “astronomical” interpretation.

Case Back

The back of a watch is the cover at the back of the case. The back can be clipped onto the caseband, or screwed to improve its water-tightness. The bottom can be transparent and then makes it possible to see the movement of the watch.
The back is often decorated with a logo or an illustration and takes up the technical characteristics of the watch (material of the case and crystal, water resistance, reference, limited series number if applicable).

Window

is an opening in the dial allowing information to be displayed. It is most often the date and the day, as on this Zeno Watch Basel.

Case

The casing refers to all the elements which surround the watch movement and which give the watch its external appearance. The case refers to the “unit” which houses the movement and dial. Case sizes can vary greatly from very small case sizes e.g. 10mm to much larger ones e.g. 50mm.

Generally, ladies’ watches come in smaller case sizes although this is not a strict rule. Watches that have a lot of complications and large movements obviously need larger case sizes to accommodate the parts. Cases can come in a range of materials from which they can be plated or made solid. Cases made with precious metals increase the cost of a watch significantly.

Micro rotor

A small rotor integrated into the caliber: see oscillating weight

Nato

At the end of the Second World War, the American army defines the AF0210 standard, which describes what can be considered the ancestor of the Nato strap: it is then a one-piece canvas watch strap. of cotton 25 cm long, equipped with a steel buckle and two loops.

Moon phases / Astronomical Moon

Moon phase watches follow the progression of the moon through its different phases the new moon, first quarter, full moon, and last quarter. The most sophisticated, with “astronomical” moon phases, need only be corrected by one day every 122 years.

Pulsometer

On a watch, the pulsometer is a graduated scale associated with a chronograph, calibrated for 15 or 30 pulsations. The user starts the chronograph when he begins to count the pulses and stops it at the last: the scale then indicates the heart rate per minute.

Annual Calendar

As everyone knows, the months have 30 or 31 days except the month of February which has 28 in non-leap years. In a leap year, February has 29 days.

An annual calendar is therefore capable of correctly displaying the date of the 1st of the month following a month of 30 days: the date will for example pass directly from April 30 to May 1 without displaying April 31. On the other hand, the transition from February 28 to March 1 requires manual intervention during non-leap years.

Perpetual calendar

The perpetual calendar is a horological complication that takes into account the fact that the 12 months of the year do not all have the same number of days, as an annual calendar can do. But the perpetual calendar also takes leap years into account.

As everyone knows, the months have 30 or 31 days except the month of February which has 28 in non-leap years. In a leap year, February has 29 days. The term “perpetual calendar” is synonymous with the perpetual calendar.

Secular calendar

To fully understand what the secular calendar is, it is necessary to read the articles on the annual calendar and the perpetual calendar. If the perpetual calendar makes it possible to take leap years into account, this will not be the case on March 1, 2100, a secular year, and therefore not a leap year. This is the particularity of the secular calendar: it takes into account the fact that a secular year is not a leap year even though it is divisible by 4.

The story is not quite over …

Regulator

A regulator is a watch whose hour and minute hands are not coaxial, i.e. they are separate. In general, the minute hand is the largest, while the hour hand is smaller and off-center. This configuration was historically preferred for precision clocks because they were more accurate. Indeed, the cogs of the two off-center hands generated less friction…

The repeater

The repeater is often considered one of the most prestigious horological complications. The invention appeared in England in the 17th century, at a time when it was not easy to read the time at night, in the dark.

To put it simply, a repeater watch tells the time using a regular chime or is triggered manually via a pusher or a lock. The first rehearsals were called “on the quarter”, that is to say, they sounded every quarter of an hour. They could also give the time on demand, to the nearest quarter of an hour. Then came the “five-minute repeats”, which sounded the hours, quarters, and five minutes. Today the most common repeaters are called “minute repeaters”.

Power reserve

The power reserve is the operating time of a watch movement when its mainspring is wound to the maximum. This implies that we are talking here about mechanical movements with manual or automatic winding. On a modern standard movement, the power reserve is typically around forty hours.

In recent years, several high-end watchmakers have developed calibers offering higher (or much higher) power reserves. For example, brands such as Lange & Söhne, Moser, and IWC, offer models with power reserves of several days, up to 31 days.

The barrel spring

The barrel spring is the component that stores the energy that will turn the watch.

Tachymeter

The horological tachymeter: on a watch, the tachymeter is a graduated scale generally placed on the periphery of the dial and which makes it possible to estimate the average speed of a vehicle by measuring the time necessary to cover a certain distance. The tachymeter scale is always associated with a chronograph.