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Tim Temple watches - Watch glossary
Category: General technical and industrial > Watches
Date & country: 08/11/2007, UK
Words: 244


Aiguilles
(French) The hands of a clock or watch.   The cuvette of a Swiss or French key-wound watch is sometimes stamped AIGUILLES as a warning that the hands are set through the nearby hole rather than by placing the key directly over the exposed end of the cannon pinion in the centre of the dial.

Alarum
Horologists seem to prefer this Shakespearean spelling for a clock or watch that sounds a warning bell at a pre-set time. Alarum mechanisms are found on some of the earliest mechanical timekeepers and were being fitted to watches before 1600.

American Gauge
A system of gauging the sizes of watch movements.   Size 0 equals 1.167' or 29.63mm and each step upwards or downwards consists of a step of 0.0333' (0.846mm);  size 18, the largest in common use, is 1.688' (45.72mm).   Sizes below 0 are expressed (in diminishing order) as 2/0, 3/0 and so on downwar

Ancre
The French term for the lever escapement in its usual 20th-century form, with the arm that carries the pallets mounted at a right angle to the lever itself so as to give a rough likeness to an anchor.

Arbor
The axle or shaft on which a wheel or pinion is mounted.

Arcading
A distinctive treatment of the minute track on some 18th-century watches;  between each pair of hour numerals the track is shaped in an ornamental semicircle.   This pattern is especially associated with Dutch watches (example).

Arnold, John
(1736-1799) Chronometer pioneer.   Born in Cornwall, Arnold first distinguished himself in 1764 with a tiny repeater set into a ring, which he presented to King George III.   He invented a helical balance-spring which came nearer to true isochronicity than anything else before Breguet (who greatly a

Balance
The component which, in a mechanical timekeeper without a pendulum, controls the speed of the mechanism by its oscillations to and fro.   Since the early 1600s it has invariably consisted of a spoked wheel (for an earlier form see Foliot).   Until the 1670s the balance-wheel performed this task alon

Balance-Spring
An alternative name for the hairspring.   The latter term is preferred in the U.S.A. but is not unknown in Britain;  in 1857 the humorous writer Tom Hood used the name ‘Harespring` [sic] for a watchmaker.

Balance-Staff
The arbor of a balance-wheel.   It is a steel rod, usually very thin (to minimise friction) and therefore easily damaged, especially in English full-plate watches where it often succumbs to accidental pressure on the unsupported cock.

Banking Pin
A pin whose function is to prevent an oscillating component – a balance-wheel or part of the escapement – from swinging too far.   It may be mounted on the moving part itself and designed to strike an obstacle if the arc threatens to become too great;  thus some verge balances carry banking-pins.  

Barred Movement
A movement in which the traditional bottom plate is replaced by a number of small brass blocks screwed into place, each supporting one wheel.   The type was developed by Breguet as a variant of the Lépine calibre and became almost universal in Swiss watchmaking by about 1850.   Also called ‘bridge m

Beat
The ‘tick` of a clock or watch, produced as a pallet comes into contact with the escape-wheel.

Beetle Hand
A pattern of hour hand used in many 18th-century English watches.   Something like a figure-of-eight laid on its side, with prongs projecting from it, lies across the main shaft of the hand near its outer end;  this is supposed to resemble the wing-cases and legs of a beetle.

Berthoud, Ferdinand
(1729-1807) Swiss watchmaker who invented a form of spring detent escapement independently of his English contemporaries Arnold and Earnshaw.   Founder of a long-enduring family firm, he is equally important for a series of technical writings on horology — in contrast to Breguet, of whom Berthoud re

Bezel
The retaining ring in which the crystal or glass is mounted.   It forms part of the case and was usually hinged to the main body until about 1880, after which screw-threaded or snap-on bezels gradually came into use.

Bimetallic
Made of two different metals, usually brass and steel, with the idea that their differing rates of expansion and contraction in response to temperature changes will more or less cancel each other out, immunising the component in question (usually a balance-wheel) against overall variation in size an

Bosley Regulator
A form of regulator consisting of a movable arm pivoted round the centre of the cock, its outer end forming a pointer which moves over a graduated scale (sometimes marked Slow[er] and Fast[er], or in French R[etard] and A[vant]);  near this end are fixed the curb-pins.   Joseph Bosley patented this

Bottom Plate
In a full-plate or three-quarter-plate movement, the plate farther from the dial.

Bow
The loop for attachment to a chain, mounted on the pendant of a watch case.   The bow is often an approximate guide to the date of the watch;  various ornamental shapes were used from about 1680 to 1820, after which a plain circular bow was generally adopted.

Breguet Hand
A hand terminating in a triangular pointer protruding from a circle, the latter having a hole cut in it slightly off-centre so that the rim is at its narrowest where it meets the pointer.   The pattern was very widely used in both clocks and watches for about fifty years from 1800.   Also called moo

Breguet Key
A winding-key incorporating a ratchet so that if turned the wrong way it revolves harmlessly instead of straining the train;  used by Breguet but apparently a slightly earlier English invention.

Breguet, Abraham Louis
(1747-1823) Swiss-born clock- and watchmaker noted for his individual ideas and incomparable craftsmanship.   He refined and popularised the Lépine calibre, using it to create watches of austere beauty (his movements are quite undecorated) and remarkably modern appearance.   He was an early champion

Brevet
(French) Patent.   Stamped on the cuvette, the word is sometimes mistaken for a maker's name (ancre and remontoir also lend themselves to this misconception);  as it happens there really was a Paris watchmaker named Brevet, although as he lived in the seventeenth century he is unlikely to cross the

Bridge
A brass or nickel block screwed to the top plate of a movement, with a hole in it (often jewelled) to support one end of the arbor of a wheel.

Bridge Cock
A cock which is secured to the movement at two points on opposite sides.   Bridge cocks were preferred by most European makers form about 1680 to 1820, whereas English makers inclined to what I have called the cantilever cock, with only one securing point.

Bridge Movement
The same as barred movement.

Bullseye
A glass or crystal of convex form with a panel ground flat or slightly concave in its centre, much used between about 1760 and 1820 but still found on some Swiss watches fifty years later.

Calibre
The physical make-up of a watch movement;  as a person may be said to be of stout, slim, massive or slight build, so a watch can be described as being of large, small, deep, slim etc. calibre.   The word is most often found as part of the phrase Lépine calibre.

Cannon Pinion
A pinion which is a friction-fit on the arbor of the centre wheel and has a tubular extension (whose shape gives rise to the name) passing through the central hole in the dial, on which the minute-hand is fitted.   On English key-wound watches the top of this extension is squared off to receive the

Cantilever Cock
This, I must confess, is not a recognised technical term but a coinage of my own for something which otherwise seems to have no specific name:  the English type of cock which is secured to the dial at one point only, by means of a screw passing through a hole in the large wedge-shaped foot, and whos

Centre Wheel
The second wheel of the train, driven (by means of a pinion which shares its arbor) from the great wheel.   The arbor forms the spindle around which the hands revolve.

Champlevé
This has two meanings:  (1) A technique of enamel decoration used on very early watches.   The metal body of the item to be so decorated is carved away, leaving its original surface only as a series of narrow walls between hollowed-out cells which are then filled with enamel — hence the French name

Chapter-Ring
The circle of hour numerals on a dial, or the part of the dial which contains these numerals.

Chinese Market
From the middle eighteenth century onward a taste for European (initially English, later Swiss) clocks and watches spread among the upper classes in China, with the Ch'ing emperors setting the example.   ‘Chinese` watches usually have very ornately engraved plates or bridges and often incorporate a

Chronograph
A watch that is both a normal timekeeper and a stop-watch.   Invented by Henri Piguet in 1861, it was a large watch with a centre seconds hand and a slider on the edge of the case to operate the stop-work.   The minute/second divisions on the dial are subdivided into fifths.   ‘Chronograph`, unlike

Chronometer
A portable timekeeper designed for the purpose of finding a ship's longitude at sea – a task which calls for exceptional accuracy under widely varying climatic conditions.   Some authorities hold that only an instrument fitted with a detent escapement deserves to be called a chronometer;  others arg

Click
A spring-loaded pawl or tongue used in conjunction with a wheel with angled teeth (in which the click engages) so that the wheel can be turned one way only.   Most familiar in association with one of the two large wheels usually visible in a stem-wound movement.

Clock-Watch
A chiming watch, distinguished from a repeater in that it sounds the hours etc. automatically as the appropriate time arrives, whereas a repeater does so only when a plunger is pressed.   Some of the earliest portable timekeepers are clock-watches.

Cock
The shaped bracket which supports the bottom bearing of the balance-wheel and to some extent protects the wheel itself.   A cock consists of a ‘foot` (or, on French, Swiss and some German and Dutch movements until the 1820s, two feet) screwed to the movement and a ‘table` extending over the balance.

Collet
A retaining-ring, usually of brass;  especially the one which holds the inner end of the balance-spring on the staff.

Compensated Balance
A balance-wheel constructed in such a way that its diameter (variations in which can affect its rate) remains constant at all temperatures, despite the tendency of its material to expand and contract with heat and cold.   This is usually done by making the rim of the wheel out of two different metal

Compensation Curb
An early form of temperature-compensation, using a bimetallic strip with one end fixed to one of the plates and the other, which is free, carrying the curb-pins.   The controlled expansion and contraction of the strip adjusts the position of the pins on the hairspring and so maintains its effective

Complicated Work
Strictly, any function in a clock or watch other than the recording and display of hours, minutes and seconds;  e.g. calendars (the most common kind), week-day indicators and moon-phase indicators.   The description is sometimes applied to an instrument which has only the normal functions but displa

Cone
In a watch fitted with a fusee, the tapered, spiral-grooved drum onto which the chain is wound and whose parabolically-curved profile provides the progressive gearing effect.   The cone incorporates the great wheel.  

Consular Case
The standard pattern of case in 19th-century British watches.   The body of the case consists of an open ring to which the back and bezel are both hinged;  a third hinge carries the movement so that this can be swung out for inspection. Inside the back there is a fixed inner panel, the dome, usually

Contrate Wheel
A wheel with teeth standing upright on its rim, so that it resembles a comb bent into a circle.  Most often found in verge watches, where the fourth wheel is of contrate form.

Controller
The oscillating component – balance-wheel, foliot, or in modern watches an electronic vibrator – which, in conjunction with the escape-wheel, meters out the motive power of the watch and makes it a timekeeper.   Where there is a separate carrier for the pallets, as in the lever escapement, this can

Coqueret
A steel plate shaped like a keyhole, mounted on the cock of an 18th or early 19th-century French or Swiss watch.   The circular end fits over the balance-staff and is pierced for the pivot;  the other end is screwed to the cock.   With the screw loosened the coqueret can be rotated, allowing for som

Crown
The milled knob on the pendant of a stem-wound watch, turned by the fingers to wind the watch and (usually) to set the hands; for the latter purpose it is pulled out or occasionally pushed in.   Stem-winding is one of the few 19th-century English innovations in domestic (as opposed to specialist and

Crown Wheel
The escape-wheel in a verge watch is sometimes so called because of the shape of its teeth.

Crystal
A rather modern term for the transparent cover over the dial of a watch (usually called simply ‘glass` until the late 19th century).   Plastic ‘crystals` began to appear soon after 1900 and are now often found as replacements on older watches. True rock crystal was sometimes used in very early watch

Cuper Family
The extraordinary achievement of this French watchmaking family, hitherto buried in the pages of Baillie's Watchmakers and Clockmakers, deserves to be put on wider display.   Established in Blois before 1600 (Barthélemy, the earliest, was born in 1555), they continued to ply the same trade in the sa

Curb Pin
The part of a regulator which controls the operative length of the balance-spring.   Generally there are two such pins side by side, the spring passing between them so that they restrict its motion;  they are mounted on an arm or quadrant which can be moved, so that they slide along the length of th

Cuvette
The hinged inner back cover of a 19th-century Swiss or French watch, pierced with holes for winding and setting (if the watch is key-wound) and often engraved with the maker's name, number, type of escapement and number of jewels. Some people also use the name for the removable dust-cap of an Englis

Cylinder
A type of escapement, especially popular in Switzerland between about 1840 and 1890, in which the teeth of the escape- wheel interact with a cut-away cylinder which forms part of the balance-staff.

Damascening
A method of decorating the bottom plate or bridges, consisting of a radial or striped design which appears to shimmer as it catches the light at different angles;  especially associated with American watches from the 1870s onwards.   It is actually a variety of engine-turning and unrelated to the da

Dart
A safety device incorporated into many lever escapements to prevent the lever and the roller from getting out of alignment.   The lever carries a pointed prong, the dart itself, between the tines of its fork;  this fits into a curved recess in a second roller, which restrains the fork if it happens

Debaufre, Pierre
(fl. 1689-1720) French watchmaker who settled in London as a Protestant refugee.   He was joint patentee with Nicolas Facio of the technique of jewelling pivot-holes (1704), and in the same year he devised the first viable alternative to the traditional verge escapement;  this so-called ‘club-foot v

Deck Watch
A large precision-made watch used on board ship for synchronising chronometers with one another or conveying their readings to the deck where solar or lunar observations were performed.   For this purpose it had to be easily carried from one part of the ship to another;  it was therefore generally p

Dennison, Aaron L.
(1812-1895)   U.S. watchmaker, pioneer of quality mass-production, whose business, founded at Roxbury (Massachusetts) in 1849, grew into the American Waltham Watch Company.

Detached
Of an escapement:  having a separate unit introduced between the escape-wheel (or the final wheel of the train) and the balance, so that the two are in contact only when the specific processes of impulse and locking require them to be so. Usually applied to the lever escapement, whose full name is ‘

Detent
In an escapement, a separate component between the balance and the escape-wheel which performs the locking function, so that the balance itself does not have its freedom of movement impaired by the need to do this.   The detent may revolve (pivoted detent) or it may consist of an arrangement of flat

Dial
The ‘face` of a clock or watch.   The familiar white or cream enamel dial began to appear at the end of the 17th century, although gold or silver dials with various forms of decoration have never quite gone out of use.

Dial
clearance between second and minute hands.   Such dials are rare until about 1810, although there is an example by Tompion dating from the 1680s.

Dome
The fixed inner back cover of an English consular case, pierced with an access hole for the winding-key.

Double Roller Escapement
A variety of lever escapement in which the balance-staff carries two rollers:  one carrying the impulse-pin and the other with a recess which engages with the safety dart.

Draw
A configuration of the locking face of a pallet which causes it to pull the escape-wheel more tightly into engagement during the locking process, producing an infinitesimal recoil in the train.   The purpose of this is to prevent pallet and escape-wheel from slipping out of engagement,

Drop
The interval between impulse and locking during which the escape-wheel, and therefore the whole train, is free to turn.

Duplex Escapement
A complex escapement invented by Pierre le Roy in about 1750 but favoured chiefly by English watchmakers in the first half of the following century.   The escape-wheel has two sets of teeth (hence the name): short ones for impulse, engaging with a cam on the balance-staff, and long ones for locking

Dust Cap
(or dust-cover).   A protective cover fitting over the bottom plate and sides of a movement, with holes cut in it for the winding-key and (usually) the table of the cock.  In English watches it is of gilt brass, removable and secured by a sliding catch;  French and Swiss watches occasionally have si

Earnshaw, Thomas
(1749-1829)   English watchmaker and chronometer innovator.  In early life he was a specialist maker of cylinder escapements, and when in 1781 he devised a spring-detent escapement he was obliged to seek the co-operation of a client, Thomas Wright.   Wright did not stir himself to obtain a patent un

Ébauche
A mass-produced movement, usually Swiss, designed to be bought in ready-made by ‘watchmakers` who would then finish, sign and market it as their own.   The 19th-century Swiss industry, while undoubtedly capable of producing articles of the highest quality, was largely built upon the volume manufactu

Elgin
(Elgin National Watch Co.)   U.S. manufacturer, founded at Elgin near Chicago in 1864, as the National Watch Company, by a group of Waltham executives who saw the need for a manufacturing base beyond the traditional east-coast locations, exploiting the rapidly expanding railroad system.   The Elgin

Enamel
A form of glass, presented in powdered form and usually coloured by means of metal oxides, which when heated (a process called fusing) sets into a hard substance which can take a high polish.   Enamelling of various kinds was used to decorate watch cases from very early times.   In about 1630 the Fr

End Plate
The centre-piece of the table of the cock, in which the balance-staff pivot is located.   In English watches (those without a jewelled endstone) it was usually of brass and soldered in place;  the French school preferred a steel plate held by screws and often covered by a coqueret.

Endstone
A jewel (ruby or, quite often in 19th-century English watches, roughly cut diamond) used as an end-plate.

England
England was slow to develop an independent watchmaking school, and few examples by home-born makers can be traced before 1600;  Bartholomew Newsam, employed by Queen Elizabeth I, was among the earliest.   A Worshipful Company of Clockmakers was incorporated in 1631;  its founder-members included Edw

English Lever
A name often used (especially by English makers!) for the tangential or side lever.

Escape Wheel
carries the second-hand, has thirty teeth rather than the usual fifteen, so that the hand makes a complete circle in fifteen seconds.   A watch with this arrangement (usually a rack-lever) can be recognised at once because the seconds dial is numbered only 5-10-15.

Escape-Wheel
The final (usually fifth) wheel of the train, bearing specially-shaped teeth which interact with the pallets.

Escapement
The ‘metering unit` which, working in conjunction with the balance or other controller, breaks down the motive force of the mainspring into controlled and regular steps by alternately delivering impulse to the balance and locking the train.   Its main components are the escape-wheel and the pallets;

Fake Fusee
(or false fusee).   A late 19th century English key-wound watch with a going barrel and an extra wheel interposed between the great wheel on the barrel and the centre pinion.   The sole function of this extra wheel is to gratify old-fashioned English preferences by making the winding action work ant

False Pendulum
A curious fad of the late 1600s:  a miniature facsimile of the bob (flat circular weight) from the end of a clock pendulum, attached to the rim of the balance-wheel and arranged so that it could be seen wagging to and fro.   For this purpose the movement was sometimes rearranged so that the balance

Fasoldt, Carl
(1818-1898)   U.S. watchmaker, inventor of a type of lever escapement and pioneer of the production of true marine chronometers in the U.S.A. (commencing 1861).

Flirt
This slightly improbable term simply means something that moves in jerks rather than continuously, like the second-hand of a modern watch.

Foliot
The earliest form of controller, consisting of a pivoted beam with weights (which might be adjustable) at either end, like a dumb-bell.   Some of the earliest watches had miniature foliots (only relatively miniature – the foliot could take up the entire breadth of the movement) instead of balance-wh

Forgery
A long-standing problem.   In the late 18th century the fashionable London maker Eardley Norton was dogged by multitudes of cheap Swiss watches bearing his name;  a few of the makers went to the extent of counterfeiting the English type of layout, with single-footed cock and engraving on the bottom

Fork
The divided inner end of the lever in a lever escapement, with two prongs or tines between which the impulse-pin engages.

Form Watch
A watch whose case is shaped to imitate something other than a watch:  a heart, a cross, a book or even a skull.   Form watches were popular in the late 16th century and again about 200 years later.

Fourth Wheel
The wheel immediately adjoining the escape-wheel.   If a subsidiary seconds dial is present, its hand will usually be fitted directly on the end of the fourth-wheel arbor.

France
France adopted the idea of a portable spring-driven time-keeper very early;  the Coudray family of Blois were producing ‘montres` before 1520.   Early French watches made much use of engraved decoration and their makers led the way in using brass rather than iron for the movement.  17th-century Fren

Free-Sprung
Of a balance-spring:  having no regulator attached.   As any kind of regulator effectively changes the shape of the spring and therefore injures its isochronous quality, it has long been the practice in instruments of the highest precision to do without the regulator.   Such a watch or chronometer r

Frictional Rest
In an escapement, a method of achieving locking by allowing one component to slide over another without meeting any actual opposing force, so that there is no recoil.   A typical example is the cylinder escapement, where the cylinder itself is configured to stop the escape-wheel teeth without pushin

Front Plate
The plate nearer to the dial.   Certain components, such as the motion-work, set-up ratchet and (if present) repeater mechanism, are usually sandwiched between front plate and dial.

Full-Plate
A full-plate movement is one in which most of the moving parts are sandwiched between two circular plates (usually of brass) separated by turned pillars.   The balance-wheel is not fitted between the plates but generally carried outside the bottom plate for easier access (occasionally, as in false p

Fusee
An ingenious device which compensates for the declining force of a mainspring as it unwinds by automatically adjusting the gearing between the spring and the train as it runs. The spring-barrel is not directly geared to the rest of the movement.   Instead, it pulls on one end of a fine chain whose o

Germany (Incl. Austria)
According to 16th-century witnesses, Peter Henlein of Nuremberg was the first to make portable spring-driven timepieces, beginning in about 1510.   Early German movements were often of iron rather than brass and included striking mechanisms and other complicated work.   The Thirty Years' War undermi

Going Barrel
A mainspring barrel which drives the train directly rather than through a fusee.   Going barrels are occasionally found as early as 1700 but were first put into regular use by Lépine and his followers from about 1780.

Grade-Name
A borrowed or fabricated name engraved or stamped on a movement as if it were the manufacturer's signature, not with any intent to deceive but purely to indicate the quality of the watch as the maker sees it.   The dawn of the practice can be seen in Britain soon after 1800;  thus James McCabe and M