Creating an edge on a bridge or plate which is at 45° to the horizontal and vertical flanks. It is highly polished and delivers a brilliant contrast with the adjacent surfaces. The finest examples of anglage will be found on high-end watches, imparted by hand. The interior angles of parts will prove the most challenging to execute.
A complication on a watch which displays the date and month and often the day as well. The movement will make allowances for the differing number of days in each month, save for February which will require manual adjustment.
Several components within a conventional watch can be adversely affected by magnetic fields. Anti-magnetic watches will often shroud the movement within a soft-iron core or Faraday cage to prevent magnetism unduly influencing the movement or causing damage to various micro-components. An Anti-magnetic watch will often specify a maximum resistance to a particular level of magnetic field expressed in Gauss (G).
A film applied to the sapphire crystal of a watch that mitigates glare. It can be applied to either the internal surface of the sapphire crystal alone or both internal and external surfaces. The latter option will often confer superior clarity, but the film on the external surface may be prone to scratching.
ATM is an abbreviation of atmospheres, sometimes shown as bar (not to be confused with bar or cock, shown below). A watch with a water resistance of 3 bar is effectively water resistant to 30 metres.
A watch movement containing an oscillating weight which captures energy from the motion of the wearer’s wrist and winds the spring barrel of a mechanical watch movement, powering the functions of the timepiece.
The balance consists of a small wheel with a spring at its core, the balance spring. The balance will rotate to and fro, setting the moving rhythm of the escape wheel and the pallet lever.
A type of bridge which is only affixed at one side to the main plate. Sometimes referred to as a cock. A. Lange & Söhne is famed for its engraved balance cocks that feature a unique motif which identifies the individual engraver who worked upon it. This is part of the savoir faire of this prestigious Manufacture in Glashütte.
A metal plate which is affixed at two points to the main plate. It is used to mount movement components and will accord sufficient space for the gear train and pinions to freely move beneath.
A term often used to identify a specific movement e.g. ETA / Valjoux Calibre 7750.
The vertical flanks of a wristwatch.
Historically, real rubies were used for jewels. As the rubies were introduced to a hole in a main plate or bridge, they sometimes would be damaged. Clearly, rubies are precious, hence, jewels were set in a chaton, often made of gold, providing a soft lining for the drilled hole and preventing damage to the ruby. Today, with the advent of synthetic rubies, there is no commercial imperative to use chatons, but some high-end watch brands continue to uphold this tradition and the inclusion of chatons is another tell-tale indication of a fine movement.
A watch equipped with a stopwatch function.
A watch regarded as especially accurate (typically no more than 5 seconds deviation in 24 hours for a mechanical movement). The watch may be independently tested to confirm this status using a laboratory such as COSC (Contrôle Officiel Suisse de Chronomètres) and will be evaluated in different positions and different temperatures to ensure consistent accuracy. A chronometer subject to testing by COSC will normally be accompanied with a certificate.
A turret-like wheel featuring several pillars which interface with a vertical clutch or horizontal coupling. This will be found on a fully-integrated chronograph movement, arguably the purist’s choice. A fully integrated movement will be less prone to damage if the reset button is pressed before stopping the chronograph. Moreover, a column-wheel chronograph will confer a superior buttery-like feel to its push pieces. Finally, the time keeping of the watch is less likely to be affected on a column-wheel chronograph when the stop-watch function is in operation.
Côtes de Genève
A decorative motif applied to movement components, often bridges, which consists of stripes created with a rapidly rotating plastic or wooden peg. This pattern often consists of parallel straight lines, but may also be presented as a series of circular concentric stripes.
A device, normally positioned at 3 o’clock, but not always, used to wind the mainspring and set the time.
Equation of Time
A watch which displays both mean time and true solar time.
Enamelling can take various forms including cloisonné, champlevé, flinqué, grisaille, miniature painting, paillonnee and plique-à-jour. Grand feu enamelling involves the application of a paint-like liquid made with powders containing metallic oxides. Each colour is applied individually, sometimes with a single-haired brush and then subject to firing in a kiln at temperatures often in excess of 800°C. The repeated firing of the metal dial surface, after each colour application, bestows wondrous hues to the dial surface which will not fade with the onset of years. Enamelling necessitates the skill of a Master Enameler who not only applies colours to the dial surface but expertly controls the heating and cooling process to prevent bubbling or cracking of the enamel. This time-consuming process necessitates much patience with some dials taking several weeks to produce. Needless to say, enamel dials are costly, but technically superior to lacquer dials. Companies known for enamel dials include DeLaneau, Patek Philippe, Piaget and Vacheron Constantin.
This is the combination of the balance wheel, balance spring, pallet fork, pallet jewels and escape wheel. The escapement divides pulses of energy sent from the spring barrel and accurately portions this energy to the gear train, ensuring it moves in a smooth uniform way.
Exhibition case back
A case back featuring a sapphire crystal to accord a view of the movement within the watch.
A fly-back chronograph may, at first glance, appear like a conventional chronograph. Often the start / stop push-piece is located at 2 o’clock and the reset function is positioned at 4 o’clock. However, a flyback chronograph offers additional functionality, proving useful to time consecutive events. The wearer can press the push-piece at 4 o’clock whilst the stopwatch hand is in operation and in one process the chronograph will stop, reset and start, proving more user-friendly.
A normal tourbillon is usually supported by a bridge both above and below its cage. In contrast, a flying tourbillon is mounted without an upper bridge, supported merely from below, providing an unhindered view of the tourbillon cage revolving.
A watch equipped with an additional hour hand used to indicate the prevailing hour in a second time zone.
See Côtes de Genève
A series of four wheels which transmit energy from the mainspring to the escapement.
Similar in appearance to Côtes de Genève, presented in parallel lines. It is a decorative motif synonymous with watches made in the famous watchmaking town, Glashütte in Saxony.
A surface decoration which may take many forms. Traditional patterns include clous de Paris, satiné circulaire and sauté piqué to name but a few. Mass produced dials will be made through a stamping process. However, the finest dials will be created using a rose-engine. The rose-engine is a manually operated lathe where the guillocher has to apply a uniform pressure to carefully cut an even pattern in the dial surface. This latter method is the preserve of the finest maisons including Breguet and Vacheron-Constantin.
An alternative name for a balance spring, found at the heart of a balance.
A regulating device which changes the effective length of the balance spring making it oscillate faster or slower. A speciality of A. Lange & Söhne is the Swan-neck regulator which, as the name implies, has a profile resembling a swan’s neck and allows fine adjustment of the rate. In the case of the movements made by this brand, it looks resplendent and sits adjacent the engraved balance cock synonymous with the Manufacture.
A clean-sheet movement design, always intended to be a chronograph rather than a Modular Chronograph, which consists of an existing movement with a stop-watch module added on top. (See column-wheel to see the benefits of an integrated chronograph).
Historically real rubies were used. Now synthetic jewels are used, made from aluminium oxide (see sapphire crystal). The jewels are used to mitigate friction, acting like reservoirs to hold lubricants and ensuring smooth operation of wheels and pinions.
The mainspring is a spring contained within the spring barrel which stores energy for powering the functions of the timepiece. The mainspring has to tolerate being repeatedly wound and unwound. Moreover, the specialist alloy used should not be adversely effected by temperature or humidity.
A watch brand who makes their own movement in-house. This degree of independence and competence often commands a price premium.
Effectively the chassis of the watch movement which other movement parts are affixed to.
A highly complicated watch, featuring hammers and gongs which aurally impart the hours, quarters and minutes on demand by sliding a lever, usually on the case band. Minute Repeaters are incredibly difficult to make and will invariably command a high price.
A module is added to an existing movement. Often this is cheaper and simpler to construct. Moreover, a modular chronograph will prove easier and less complicated to service and repair when contrasted with an Integrated Chronograph.
A Push-Piece on a chronograph which starts, stops and resets the stopwatch function. It can sometimes be incorporated within the crown of a movement. The beauty of a mono-pusher is that it delivers a charming simplicity of line.
A process of removing surplus material from a movement to allow an enhanced view of the micro-components within and, in some instances, grant a view through the movement from front to back. To open-work, or skeletonise, a movement necessitates much skill as it requires the artisan to remove superfluous material without compromising the rigidity of the movement. Some movements will involve taking existing movements and open-working them with a series of saws and files. Conversely, some movements are designed from the outset as open-worked and are the outcome of a clean-sheet approach. Bovet has gained a well-respected reputation for its open-worked movements which incorporate sublime engraving on the surfaces of each narrow section of the skeletonised structure within.
A series of partially overlapping dots applied to the main plate of a movement, created with a rapidly rotating abrasive rod.
A highly complex complication, these timepieces display the date, month and often the year. Moreover, they may also show the day and moon-phase, but not necessarily. The movement will make allowances for the differing days in each month including February. These watches only require adjustment once every 100 years, on each secular year e.g. 2100, 2200, 2300.
Poinçon de Genève
The Poinçon de Genève is an official seal, sometimes referred as the “Seal of Geneva”, conferred to high-end watches made within the canton of Geneva that meet stringent guidelines. The requirements of the seal are very onerous requiring considerable effort to meet. Moreover, frequent inspections are made to establish that all necessary criteria are being met.
A function on a watch which shows the amount of energy held within the spring barrel(s). This can often be an arc-like scale depicted on the dial surface but, over the years, some manufacturers have indicated the energy stored using various forms and in some cases show this function on the case back.
The pushers, typically found on a chronograph and usually positioned, but not always, at 2 o’clock (stop/start) and 4 o’clock (reset).
Meaning “catch up” in French, this is is a particularly complex chronograph to produce. Two central chronograph seconds hands traverse the dial in unison, one superimposed above the other. To the casual observer it appears as though there is only one hand in existence. However, pressing an additional push-piece, often positioned at 10 o’clock, the wearer is able to time a separate event, the upper central chronograph seconds hand will stop and the lower split seconds hand will commence recording the second elapsed time interval. This complication allows the wearer to time two separate events precisely. If the push-piece at 10 o’clock is pressed again, the split seconds hand immediately catches up with the stop watch hand and both continue to run in tandem.
The chronograph counters / sub-dials found on a watch equipped with a stopwatch function
A hand which arcs along an adjacent scale and then jumps back to a starting position. For example a retrograde or jumping minutes display will see the hand traverse a crescent-like scale from zero to 60 and then spring back to zero again. This form of display is very engaging but can consume more power as a result of its energetic motion.
The rotor is an oscillating weight in an Automatic watch.
A synthetic glass-like material made from aluminium oxide. The “glass” of many modern watches will be made of this material as it is very hard and resistant to scratching. It is often colourless (corundum) but can also be coloured and used as a synthetic jewel e.g. rubies, sapphires
Small weighted screws are threaded through the circumference of a balance wheel and can be tightened or loosened to poise the movement and ensure accurate operation. A screwed-balance is more costly to produce than a non-screwed item and is often an indication of fine quality.
Seal of Geneva
See Poinçon de Genève
A glass-like material, sometimes referred as Silicium, which is increasingly being used in watchmaking. The material is non-magnetic and not subject to corrosion. Furthermore, it can be formed into shapes not previously possible using traditional materials. In 2013, Girard-Perregaux employed silicon to make the purple coloured blade at the heart of its innovative Constant Escapement L.M timepiece.
See Open-worked Movement
A series of concentric circles found on the surface of sub-dials
A spiral-shaped motif applied to barrel covers, oscillating weights and ratchets.
Similar to a minute repeater, the watch strikes automatically on the hour (petite sonnerie) or quarter hour (grande sonnerie). The watch, unlike a minute repeater, does not have the facility to aurally convey the time on demand.
A spring barrel is a small drum-like vessel containing the mainspring which turns freely on an arbor and features teeth on its outer edge. The wheel interacts with the gear train, releasing energy and ultimately providing the power to drive the functions of the watch.
A non-radioactive luminous substance often applied to hands and hour markers to aid legibility in restricted light.
A scale usually shown on the outer edge of the dial, dial flange or bezel which features on some chronographs and is used to calculate the speed of a moving object.
The regrettable consequence of a watch being exposed to a sudden change in temperature which can lead to the sapphire crystal cracking, water ingress or condensate forming within the watch. It is for this reason a watch should not be worn in a jacuzzi or sauna.
The tourbillon, the French word for “whirlwind”, is a device patented by Abraham-Louis Breguet in 1801 to counter the adverse influence of gravity on the balance of a pocket watch. The escapement is mounted within a cage which revolves on an axis, negating the effects of gravity on the balance as it freely rotates and makes one full rotation in a predetermined period e.g. a one-minute tourbillon. Pocket watches were typically held in one plane and the invention by Breguet conferred enhanced accuracy. Clearly a wristwatch will be held in a myriad of positions, so its functional benefit has been somewhat reduced. However, the rationale for purchase is that a tourbillon demands great expertise to bring to fruition and is a wonderful expression of watchmaking skill. Furthermore, some watches freely disclose the tourbillon cage on the dial providing a captivating spectacle for the wearer to enjoy. Some brands have sought to refine the tourbillon for use in a modern wristwatch by incorporating one cage inside another, with each cage oscillating in different planes and at different rates. Arguably one of the finest exponents of tourbillons is Greubel Forsey who creates Double Tourbillons and even Quadruple Tourbillons.
Vibrations per hour
The balance spring will oscillate at a pre-determined frequency. This is often specified in hertz (Hz) or vibrations per hour (vph). Typically watches will have a frequency of 2.5 Hz (18,000 vph), 3Hz (21,600 vph) or 4Hz (28,800 vph). Zenith caused a sensation at the time it launched its fully integrated chronograph, the El-Primero which has a frequency of 5Hz (36,000 vph). Today, some companies have produced watches with even greater frequencies, partly through the arrival of new technologies such as silicon. A recent example of this is the Chopard LUC 8 HF, a chronometer with a frequency of 8 Hz (57,600 vph).
A watch complication invented by Louis Cottier with a rotating disc encircling the dial which can be used to simultaneously show the prevailing time in several locations around the globe.