Magnetic pivot An invention by Breguet that allows the balance staff, which holds the balance, to be held in part-suspension between two powerful micro-magnets. The magnetic pivot consists of a carbon-steel balance staff and a rare-earth magnet behind each end-stone. One of the magnets is stronger than the other so that the balance staff is in permanent contact with the end-stone on the dial side. The balance thus appears suspended between two end-stones supporting the balance pivots, automatically acting as a shock absorber by adjusting and re-centring in response to any blows or impact. Breguet received its well-deserved patent for this truly revolutionary design on 9th November 2010.
Magnetic strike governor A silent regulator developed and patented by Breguet that uses magnets to eliminate noise, wear and excessive energy consumption in mechanical sonneries (see Sonnerie), while adding increased precision as well. Breguet introduced the magnetic strike governor in its “La Musicale” model which is offered with chiming “The Thieving Magpie” by Rossini and “La Badinerie” by J.-S. Bach.
Mainspring Also known as a balance spring, the mainspring is a coiled strip of metal, gold, silicon or other alloy set inside the spring barrel. It is the main driving force in a clock or watch. When fully wound it imparts energy to the gear train prior to the escapement and subsequently impulses the balance via the horns of the pallet fork. When viewed by the naked eye, the mainspring is noteworthy for its concentric “breathing” or pulsations as it oscillates back and forth. See also Breguet balance-spring.
Minute repeater A watch or clock that “repeats” the hours, quarters and minutes on demand by activating a sliding lever or pressing a button on the side of the case. The sound is subsequently generated by two hammers striking on a gong. The hours are indicated by a low tone (dong) and minutes by a high tone (ding) and quarter hours by a double tone (ding-dong). A minute repeater differs from a striking watch that sounds the time automatically at preset intervals. A further variation is the chiming watch that plays a chime or musical theme on demand, for example, Breguet’s La Musicale ref. 7800. Some repeaters also have three gongs, called a carillon. See also Sonnerie.
Note: The minute repeater and its many variations is universally regarded as the ultimate achievement in high horology. A repeater is not only a watch or clock but a musical instrument. The finest repeaters are costly and produced in extremely small quantities. Further variations include cathedral gongs that have a longer and deeper (richer) sound as well as Westminster Chimes, which gloriously reproduce the peal of bells that rings out from the Houses of Parliament. In all its iterations, the minute repeater stands at the apex of grand complications.
Pare-chute A shock protection system invented by Breguet in 1790, called pare-chute or parachute. This device protects the pivots of a balance from damage if the watch is dropped or otherwise impacted. This is achieved via the bearing which is fitted into a spring that flexes with the inertia of the balance so that any shocks are absorbed by the stronger pivot shoulders of the balance staff. Also known by its French name suspension élastique.
Perlage A surface decoration applied to the plate, usually made up of overlapping swirls of dots called “circular graining”. They are between 2-5mm in diameter and applied with a rotating wooden or plastic peg by hand using a mounted or standing drill bench. Perlage is both decorative and has the added benefit of attracting tiny particles of dust, since the grain acts as a kind of carpet within the watch or clock case. Some surfaces are treated with Geneva stripes or “côtes de Gèneve”, known as French or Geneva waves, often found in the watches of A. Lange & Söhne as well as Glashütte Original. Not all plates are treated in this manner, however, and a number of high-end clocks and watches contain plates that are mirror polished rather than grained or brushed.
Perpetual calendar A perpetual calendar automatically adjusts for all calendar months including February. A part called a cam forms a mechanical memory, which reproduces the four-year cycles that include leap years. The majority of perpetual calendars currently on the market will need to be adjusted again on 1st March 2100 because it is a secular year and not a leap year. (The secular year does not leap and occurs every time the first year of a century is not divisible by 400.) A perpetual calendar represents one of the most prestigious complications in watchmaking showing the day, date, month, leap year and the phases and age of the moon.
Note: Never attempt to adjust a perpetual calendar without first reading the manual for the particular timepiece in question. There will be a proper sequence of events which, if not followed, could damage the watch mechanism and in almost all cases a special stylus must be used to depress the buttons for setting the perpetual calendar which are recessed into the side of the watch or clock case.
Plate The plate or base plate looks like a coin with one or more layers, with plenty of holes and cavities for screws and other essential components that form part of the movement: that is, the movement sits on top of the base plate and is secured to the plate via bridges. Essentially, the plate holds everything together and its size and shape reflects that of the watch case (round, square, tonneau or asymmetrical). In high horology, base plates may be decorated and hand finished with beautiful anglage along the edges.
Power reserve display The power reserve display or indicator is a small hand or needle on the dial side of a watch or clock showing the amount of energy left in the mainspring. This feature can be found on any automatic or manual timepiece, regardless of the cost, although most timepieces do without it. Most mechanical watches have a power reserve of 35 to 45 hours but some high horology timepieces can boast of phenomenal power reserves of up to ten days and more.
Reference Number Breguet gives each clock or watch a model reference number and a separate reference number is assigned to the movement (calibre). Both of these together represent the origin or “birthdate” of the timepiece in question and may be used to verify the watch’s authenticity and provenance.
Regulator (display) Once upon a time, the regulator was a precision clock in the watchmaker’s workshop that gave the reference time to which all clocks and watches in production were set or adjusted. To ensure maximum precision, the hands are positioned above the wheels inside the movement. The hour, minute and second hands all sit on individual axes i.e. the hands are not coaxial or placed on the same axis, usually at centre.
Breguet and other manufactures have made regulator wristwatches wherein the general dial layout comprises a large centrally located minute hand, with a separate hour hand and second hand displayed in subdials at twelve o’clock and six o’clock, or any variation thereof. Breguet refs. 1747, 3680, 3690 and 5187 are examples of fine wristwatch regulators, as well as Breguet’s grand complication ref. 5307, featuring a stunning regulator dial with tourbillon.
Note: See Index for a different meaning of the word ‘regulator’.
Rotor An essential component in an automatic or self-winding watch, the rotor, also called the oscillating mass or winding weight, consists of a weight that winds the mainspring as a result of the wearer’s natural movements. Rotors can wind the watch bilaterally or unilaterally and are usually centred above the movement (some high-end movements boast off-centre rotors and micro-rotors that are visually attractive).
Sapphire crystal Sapphire crystal or crystal is the glass covering the dial of a watch or clock. Watches with open case backs may also feature sapphire crystal on the reverse side. It serves to protect the watch or clock from dirt, dust, and moisture.
Altogether there are three types of crystal: a) sapphire crystal or synthetic sapphire, known as aluminium oxide which is lab-grown and can be colourless (corundum), blue (sapphire), green (emerald) or red (ruby) and nowhere the cost of natural crystal; b) acrylic crystal or plexiglass, which is similar to plastic, making it durable, light and affordable, however, it is prone to scratches and may crack but not shatter if badly impacted; and c) mineral crystals, which are made of glass and inexpensive compared to sapphire crystals but scratch easily.
Of all three, sapphire crystal is the most popular among well-made watches for its toughness, durability and because it is virtually scratch-proof – only diamonds are harder. Last but not least, sapphire crystals offer water resistance to the deepest fathoms of the ocean that cannot be matched by plexiglass or minerals.
Note: Plexiglass was made famous by the original Omega Speedmaster chronograph for use by NASA in space exploration. The reason being that plexiglass does not shatter.
Screw balance This describes the tiny, weighted screws you will see in the rim of a compensation balance. They can be adjusted to achieve a precise impetus or to vary the effects of the compensation. It is a sign of effort by the watchmaker and usually found in more high-grade movements.
Secret signature The success of Breguet led to the rise of counterfeit dials and pocket watches. In 1795, Breguet devised a countermeasure called “the secret signature”. A tiny signature of the eponymous founder’s name “Breguet” is etched into the dial. This signature is only visible under oblique light or under a good loupe. It remains a feature of most Breguet dials to this day.
Silicium/silicon In 2006, Breguet once again achieved a major breakthrough with the development of silicon parts in watchmaking. Silicon is impervious to magnetism and highly resistant to corrosion and wear. It reduces inertia, is lighter and harder than steel, and Breguet uses a special thermal oxidation process to make silicon resistant to the effects of temperature. Silicon requires no lubricant and minute parts can be manufactured with greater accuracy and replaced where necessary.
Note: In 2006, Breguet led led an alliance which heralded a mainstream silicon revolution: Breguet, Patek Philippe, and Rolex jointly drew on the resources of Neuchâtel’s Centre of Swiss Electronics and Microtechnology. And while Ulysse Nardin debuted its Freak wristwatches in 2001 with silicon components, it was not until 2006 that the great manufactures adopted the widespread use of silicon successfully in the manufacture of precision escapements. For example, Breguet developed the Type XXII 10 Hz with a silicon escape-wheel, lever and flat balance spring, which debuted in 2013 together with the Classique Chronométrie 7727.
Simple watch Breguet used this term to describe clocks and watches with no complications to the movement.
Skeletonisation Skeleton or squelette watches are high-end artisan timepieces wherein the components of the movement have been reduced down to the smallest number of plates and bridges possible. Skeletonised or open-worked watches therefore reveal the calibre front and back through sapphire crystals without the need for a dial. The act of making the entire interior of the watch visible means squelette watches are often decorated by hand by a master guillocher or engraver. All interior angles are usually bevelled or chamfered and polished to highlight the overall craftsmanship, engraving and motifs on display.
Note: André-Charles Caron (1697-1775), royal clockmaker to King Louis XV of France, is often regarded as having pioneered open-worked movements. Caron worked for the French Royal Court between 1720 to 1760.
Sonnerie Similar to the minute repeater except that the sonnerie, or strike, sounds the time automatically – au passage (in passing) – every hour (Petite Sonnerie) or quarter hour (Grande Sonnerie). The most difficult complication together with the minute repeater, several prestigious sonnerie watches also offer the owner three modes to choose from: Grande Sonnerie, Petite Sonnerie and silence.
Note: Philippe Dufour created his Grande et Petite Sonnerie minute repeater pocket watch in 1983, producing five further examples. Dufour introduced the wristwatch version in 1992 for which he won the gold medal at the World Salon of Watches in Basel for technical innovation. This watch consists of some 420 parts made by hand and assembled in 2,000 hours. Gérald Genta also designed a complicated sonnerie in the early 1990s and debuted his Gerald Genta Grande Sonnerie in 1994.
Souscription watch An ingenious marketing campaign devised by Abraham-Louis Breguet: “the subscription watch”. Breguet was interested mainly in reviving his business after the devastating effects of the French Revolution. Part payment was made by the customer at the time of ordering and upon completion of the watch, the outstanding balance was paid.
Split-seconds chronograph A chronograph with two superimposed second hands, also known by its French name rattrapante: to ‘split’ or rattraper – to ‘catch up’. It means two chronographs combined in one watch or stopwatch. The user starts the chronograph and pushes a second button to halt the first second hand, while the other continues to run. This is achieved via a special dial train lever that causes the two second hands to ‘split’, which allows for the measurement of an intermediate time. To measure the ‘split’ the user simply depresses the start/stop button at 2 o’clock. The same button that is used to split the second hand is pushed to bring them back into alignment. The chronograph will continue to run unless it is stopped or reset.
Split-seconds chronographs belong to the family of grand complications and at the highest levels, represent some of the rarest watchmaking skills outside of the minute repeater or tourbillon. They are sometimes referred to as double chronographs or Doppelchronograph in German.
Note: Most split-seconds chronographs have standard push-pieces at 2 and 4 o’clock plus a push-piece at 8 or 10 o’clock for the split-second. The user actuates the chronograph at 2 o’clock and depresses the push-piece at 8 or 10 o’clock for the split-second. Some split-second chronographs have a monopusher at 2 or 3 o’clock which eliminates the need for a push-pieces on the other side of the case. There are other variations for operating a split-seconds chronograph and the user should understand the sequence first before attempting to operate the split-seconds mechanism. It is also important to remember that a split-seconds chronograph is not a flyback chronograph, save for rare exceptions, and the user must be familiar with the sequence of operation when using any complication.
Spring barrel A box or circular container in which the mainspring is coiled. It is the main energy source in a mechanical watch, whether automatic or manually wound. There are three types: first, a standing barrel fixed to a watch plate where the barrel arbor passes through it and carries a toothed wheel coupled to the arbor; second, a fusée-and-chain transmission rotated on its arbor, usually the reserve of grand complications and most typically displayed on the main dial through a sapphire crystal; third, the going barrel which, like the fusée-and-chain, rotates on its arbor but has teeth cut into the periphery which directly drive the gear train. The third system is simple and takes up less space in a watch, although it does not compensate for the diminishing power of the spring as it unwinds.
Sympathique A term used by Abraham-Louis Breguet to describe a standing clock which contains a recess for housing a wristwatch case so that it may be automatically set and wound daily by the clock. The Sympathique and wristwatch system is still sold by Breguet as the Sympathique No. 12 and represents the most exotic way of “re-charging” a wristwatch.
Swan-neck fine adjustment A fine part whose shape looks like a swan’s neck. The swan-neck is a regulating mechanism to adjust the rate of the movement instead of an index. Most often found in fine watchmaking and visible through transparent case backs.
Tachymetre A scale or slide rule used for measuring speed or distance. This is commonly found on the bezel, dial or flange of a chronograph wristwatch. The scale value is 3,600 (number of seconds in one hour) which allows the user to convert elapsed time (in seconds per unit) to speed (in units per hour). To measure speed, the user starts the chronograph on demand at a beginning marker and stops the second hand when the object has passed a second marker. To gauge the speed the user needs to know the set distance between two points and upon stopping the chronograph, is able to read the tachymetre to determine the value. To measure distance, the user needs to know his or her travelling speed and this must remain constant. If you are travelling at 60 mph you start the chronograph and stop it when the second hand reaches 60 on the tachymetric scale. You have then travelled 1 mile.
Note: A tachymetre is a neutral scale that can be used for any unit of speed or distance (kilometres, metres, miles etc.) as long as the same unit is used for the calculation being made. It is important to remember that the tachymetric scale only measures average speed or distance in units of 60. Therefore, extra calculations are required for events longer than 60 seconds (slow events) by reading half of the event against the tachymetric scale to obtain a reading and then doubling this figure to achieve the final result. Since the tachymetric scale begins at 500 units it is not conducive for resolving measurements of less than 7.2 seconds (fast events).
Tact watch (montre à tact) Also known as a ‘blind’ watch and developed by Breguet in 1799. The montre à tact featured a single large revolvable hand on the front or back cover of a pocket watch. The hand can be turned until arrested by a stop in the movement and the time can be ‘felt’ by the position of the hand relative to the hour markers around the edge of the case. A tact watch proved useful not just for the blind or vision impaired but afforded one the courtesy of checking the time without making it too obvious in company.
Tourbillon The tourbillon, or ‘whirlwind’ in French, is by far Breguet’s most famous invention. Breguet was known to have worked on the Régulateur à Tourbillon around 1795. The patent for the Tourbillon Regulator was registered on 26th June 1801, designed to compensate for the influence of gravity on the balance of a pocket watch that was customarily worn or carried vertically. It is a revolving carriage to carry the escapement of a watch that rotates completely on its axis continuously through 360 degrees which negates the effects of poising errors in the balance.
Breguet constructed carriages in one-minute, two-minute, four-minute and six-minute periods, all of which are regarded as outstanding horological achievements. The aesthetics of a masterfully executed tourbillon remain highly prized among collectors to this day even though a tourbillon in a wristwatch does not lead to greater accuracy but remains purely a visual delight.
Note: The first known example of a tourbillon in a wristwatch is by French watchmaker Lip, dating from the 1930s. Omega followed up with a small run of models in 1947 which were intended for observatory competitions. Latterly, watchmaker Franck Muller is sometimes credited with being the first to expose a tourbillon on the dial side in 1984. Audemars Piguet then released the first self-winding tourbillon wristwatch in 1986. Breguet celebrated the birth of its founder in 1997 with the 250th Anniversary Collection, which included a small number of grand complication, minute-repeating, perpetual calendar tourbillons that are highly prized by collectors and rarely seen.
Vibration frequency (vph) Mechanical clocks and watches all beat at a certain frequency measured in Hertz (Hz) or vibrations per hour (vph). This is a result of the spring which causes the balance to oscillate at a given frequency. Most wristwatches commonly tick at 4 Hz (28,800 vph) or 3 Hz (21,600 vph). A few watches, including some grand complications, beat at a slower rate of 2.5 Hz (18,000 vph), for example, Breguet’s Héritage 5497.
Zenith’s El Primero, launched in 1969, was the first serial movement beating at a frequency of 5 Hz (36,000 vph) and it boasted a power reserve of 50 hours.
Note: Breguet achieved a world first in 2013 with the release of its Type XXII, a dual time 60-minute flyback chronograph beating at 10 Hz (72,000 vph) for the time as well as the chronograph. This was followed by the Classique Chronométrie 7727 which won the coveted 2014 Grand Prix d’Horlogerie de Genève. A hallmark of hi-beat watches is that the seconds hand is visibly much smoother as it traverses the dial but the power consumption is correspondingly high and these watches must be wound, or worn, regularly.
Watch servicing All mechanical clocks and watches are engines that require routine maintenance from time to time. Servicing a clock or watch is recommended to be done around every five years by a qualified professional. The exterior of clocks and watches should be cleaned or wiped regularly with a soft lens cloth to minimise the build up of dirt, dust, grime, water and natural oils from wearing or handling the timekeeper.
Water resistant Water resistant means any timepiece, be it quartz or mechanical, which can be safely submerged under water. This is usually measured in increments of one atmosphere e.g. atm/atu [atmospheric under-pressure], or bar, equal to 10 metres of water pressure.
Note: The crown must be safely and securely screwed down as well as any other screw-down push-pieces that your timepiece may have. As a rule of thumb, vintage watches and fine timepieces should not be submerged in water. Better safe than sorry and that goes for mechanical chronographs too, which should NEVER be used under water. Dress watches and high horology timepieces are often advertised as having water resistance but are better kept on dry land and assumed to be only dust/humidity proof and rain resistant at best. Diver’s watches with a minimum water resistance of 200-300m are ideally suited for regular aquatic activity and professional dive watches should meet the standards of ISO 6425.
Photos © Montres Breguet SA. Fair use
Glossary © BreguetBlog.com 2019. All rights reserved