Horological Terminology RomanDial

Horological terminology

Action. A term used to denote the arc of the vibration of the balance.

Adjusted. A term referring to the temperature correction and positional timing of a movement. An adjusted movement would be in five positions e.g. dial up, dial down, pendant up, pendant down, pendant right pendant left and tested at 2 temperatures e.g. 5 and 30 degrees Celsius.

Albert. Watch chain usually attached to the waistcoat.

Amplitude. The swing or extent of balance.

Ancre. Swiss term for lever pallets.

Annular Balance. The circular balance fitted to watches.

Arabic. A style of watch face numeral e.g. 1, 2, 3, etc.

Arbor. The steel shaft or axle that the wheels and pinions are carried on.

Argentan. Nickel alloy used in watch case making 20% Nickel 60% copper 20% zinc also known as Nickel Silver.

Assaying. The method of testing metals.

Automaton. A watch with moving figures operating in conjunction with the mechanism.

Automatic Winding. A mechanism that allows the watch to be wound by wearing it.

Balance. The controller or governor of a watch escapement, sometimes referred to as "balance wheel" this is an incorrect term.

Balance Cock. The bridge or bar supporting the balance in position.

Balance Screws. Screws attached to the balance used for timing adjustments.

Balance Spring. The spring controlling the balance sometimes called "hairspring".

Balance Staff. The shaft of the balance.

Brass. An alloy of copper and zinc, 2 parts copper 1 part zinc.

Breguet Balance Spring. Where the outer coil is bent over the volute, named after the inventor A.L Breguet, also called "Overcoil."

Barrel. The container of the watch main spring.

Beat. The tick of a watch as a tooth from the escape wheel drops on to the locking face of the pallets

Bezel. The top part of a watch covering the face containing the crystal.

Bi-Metallic, The use of 2 metals bonded together.

Blueing. A colour finish given to steel by heating.

Bridge. A bar with two supports, with only one support it is termed a cock.

Bow. The hanging ring of a pocket watch.

Box Chronometer. A marine chronometer, see also chronometer.

Cannon Pinion. The pinion that the minute hand is attached.

Cap Jewel. Th flat jewel that the pivot rests on, also called the endstone.

Capped Jewel. A jewel hole with an endstone.

Carat. the standard to define the quality of gold.

Cartouche Dial. Engraved metal dial with enamel numerals.

Center Seconds. Where the seconds hand moves around the center of the dial, also termed "Sweep Seconds."

Chain (Fusee). The chain that connects the spring barrel and the fusee cone.

Chapter Ring. The ring marked on the dial showing the hour divisions.

Chatelaine. A ladies pocket or fob watch.

Chronograph. A mechanism that enables the watch to be started stopped and returned to zero usually having a center seconds hand.

Chronometer. A watch usually having a "Detent" escapement made for determining the longitude at sea. Today a Chronometer is a watch that has passed tests at one of the Bureaux Officels.

Clock Watch. A watch that strikes the hours and also repeats the hour, quarter and minutes as required.

Cock. A bracket with one support distinct from a bridge that has 2 supports.

Coin Watch. Where the watch case has been made from a coin.

Compensating Balance Spring. A balance spring made of an alloy that remains unaffected by temperature variations.

Compensating Balance. A balance made from nickel steel with a brass layer bonded to the outside producing a bi-metallic balance expanding and contracting relative to the center compensating or the changes in temperature.

Complicated Watch. A term used to indicate other than a plain timepiece such as chronographs and repeaters.

Consular Case. A case resembling a pair case with a high domed glass, popular in France.

Crank Escapement. The double Virgule escapement by Lepaute.

Crank Roller. A form of lever escapement by Massey of Liverpool.

Crown. Keyless winding button mounted on top of the pendant.

Crown Wheel Escapement. Refers to the crown wheel in a verge escapement.

Curb Pins. The pins fitted to the index (regulator) which embrace the balance spring.

Cut Balance. See compensation balance.

Cylinder Escapement. A frictional rest escapement invented by Tompion, Booth and Houghton in 1695.

Dead Beat Escapement. George Graham 1715.

Deaths Head Watch. A watch case made in the shape of a skull.

Decimal Watch. A watch with the dial divided into 10 instead of 12 hours.

Dial. the face of a time piece.

Dumb Repeater. A repeating watch in which the hammers strike the case rather than a bell or gong.

Duplex Escapement. A frictional rest escapement where the escape wheel has a double set of teeth.

Dust Cap, Cover. Cover used to protect key wind watch movement from dust.

Earnshaw's Escapement. Chronometer escapement.

Ebauche. An unfinished movement without escapement supplied with plates, cocks, bridges and train.

Engine Turning. 19th century case decoration.

English Lever.Refers to a lever watch manufactured in England, but more generally to define the ratchet toothed escape wheel and the conventional type of English lever escapement.

Escapement. the part of the watch movement that which allows the power driving the movement to escape in a controlled manner.

Face. Another name for the watch dial.

Figure Plate. The dial indicating the amount of regulation, Tompion style regulators.

Fob. A decorative attachment to the pocket watch.

Fourth Wheel. Usually drives the escape wheel and carries the seconds hand.

Free Sprung. A watch without an index, regulation is achieved by timing screws on the balance.

Friction Rest Escapement. Where the escape wheel is in constant contact with the balance e.g. Virgule escapements.

Full Plate. Refers to the watch movement design, the top plate covering the movement and the balance and balance cock being placed above.

Fully Adjusted. Refers to a movement that has been adjusted for temperature changes and positional changes.

Fully Jeweled. Refers to a watch having 15 or more jewels with third and fourth wheel jeweled both top and bottom, jeweled escape wheel and lever top and bottom, pallets, balance with top and bottom jewels plus end stones and jeweled impulse pin.

Fusee. The spirally grooved pulley used to equalise the pull of the mainspring.

Fusee Chain. The chain which conveys the power of the main spring to the fusee.

Geneva Movement. Refers to the bar type movement in which the top plate is replaced with bridges and cocks.

Gilt. A gold coating applied to base metals such as brass.

Going Barrel. The barrel of the mainspring of a watch on which teeth are provided so that the mainspring power is conveyed directly to the train.

Gold Filled. Another term for rolled gold, a thin sheet of gold bonded to case metal.

Goliath. Refers to a large watch used as a clock typically with an 8 day movement.

Gun Metal. An alloy of copper and tin Often watches with cases made from steel and the chemically coloured or incorrectly labeled as gun metal.

Half Hunter. Watch case with a small central aperture in the front lid to show the dial and hands.

Hall Mark. The official control of gold and silver with markings for date location of assay office and quality of the gold or silver.

Hand Set. Refers to the setting of the watch hands by means of a key

Hands. The pointers of a watch showing the time, sometimes referred to as fingers.

Hard's Balance. A chronometer balance by William Hardy 1804. Designed to reduce temperature error.

Hogs Bristle. The predecessor of the balance spring.

Horology. The science of the construction of mechanisms for measuring time.

Hour Hand. The pointer of a watch indicating the hour.

Hunter. Where the face of a watch is fully covered by a cover or lid.

Impulse Pallet. The pallet of the impulse roller which receives the impulse.

In Beat. A term used to signify that the watch action of the escapement is running evenly.

Incabloc. A shock resisting system, the jewel holes and end stones of the balance have some give when the watch receives a jolt.

Index. Also know as the regulator to manually compensate for time errors.

Index Pins. The pins which embrace the outer spiral of the balance spring.

Isochronous. When the watch keeps the same time whatever the arc of the balance.

Jewel. Bearings made from precious stones such as ruby.

Jewel Hole. The part of the jewel that the pivot passes through.

Karrusel. A revolving escapement by Bonniksen 1893, designed to reduce vertical positioning errors.

Key. Key or winder, the winding device of a watch.

Keyless. The ability to wind and set hands of a watch without a key usually refers to a crown winding watch.

Key-Wind. A watch of earlier type that is wound and hands are set with a key.

Kullberg's Ballance. Invented by Victor Kulberg. an auxiliary compensation balance.

Lever Escapement. Invented by Thomas Mudge in 1759 getting its name from one of the parts which acts as a lever.

Ligne. A unit of measurement for watch movements 1 Ligne = 2.256mm.

Litherland's Escapement. A rack and pinion escapement by Litherland 1792.

Loupe. A magnifying eye glass.

Lunar Work. The mechanism of a watch showing the phases of the moon.

Mainspring. The main spring of a watch which drives the watch.

Maintaining Power. The device used to maintain the driving power of the mainspring while the watch is being wound.

Manivelle Escapement. A form of Vergule escapement, by Lepaute 1720.

Mercer's Balance. An auxiliary compensation balance by Thomas Mercer 1822 -

Minute Hand. The hand of a watch that indicates the passing minutes.

Minute Repeater. A watch that strikes the minutes quarters and hours.

Mono-metal Balance. A balance made from one metal as apposed to I bi-metal balance.

Moon Dial. The dial showing the phases of the moon.

Movement. The mechanism of the watch.

Mudge's Escapement. The first detached lever escapement 1754.

Navigator Watch. A watch giving the time in various cities of the world.

Oignon. Large and bulbous watch made in France, late 17thC early 18thC

Open Face. Refers to a watch not fitted with a cover.

Over Banking. Where the the impulse pin passes to the wrong side of the lever.

Pair Case. Two watch cases where the movement is fitted into one case then is fitted into an outer case.

Pendant. The part of the watch case that has the Bow fitted.

Pivot. The reduced end of of an arbor.

Pivot Hole. The hole, jewel or bush in which the pivot runs.

Plates. The brass disks supporting the train of the watch.

Pocket Watch. A watch made to worn or carried in the pocket.

Positional Errors. Positions at which the watch will run faster or slower, there are 5 positions measured, Dial Up, Dial Down, Pendant Right, Pendant Left and Pendant Up.

Precision Watch. Refers to an adjusted watch.

Push Piece. The part of the watch case that is pushed to release ever the front cover in hunter watches or the rear cover to access the winding arbor.

Rack Lever Escapement. A lever escapement using a toothed rack in place of the table roller and impulse jewel.

Railway Time. Greenwich Mean Time.

Regulation. The term used to describe the adjustment of the time keeping of a watch.

Repeater. Refers to a watch where the hour, quarter and minutes can be sounded by pressing a button.

Repousse. Decoration using hammers and punches to push metal into a relief pattern.

Rolled Gold. A thin layer of gold rolled onto a base metal.

Roller. The disc or platform that holds the impulse jewel or pin.

Savage 2 Pin Escapement. A variation of the lever escapement having 2 pins in place of the single impulse pin.

Seconds Hand. A hand showing the passing of the seconds.

Set Hands Arbor. The arbor of the watch where the hands are set by using a key.

Set Hands Square. The square end of the set hands arbor that the key fits over.

Shagreen. Hide from a shark or ray.

Split Seconds. A Chronograph that has 2 seconds hands each running independently.

Stackfreed. An early device before the introduction of the fusee used to equalise the force of the mainspring.

Stem. The winding shaft of a keyless wind watch.

Stem Set. A watch that has its hands set by pulling out the crown button.

Stem Wind. Keyless winding of a watch.

Sunk Seconds. A seconds dial sunk below the level of the main dial.

Three Quarter Plate. A design of watch movement where the top plate is cut away allowing the balance to be set at a lower level.

Timekeeper. Any device showing the time of day.

Timepiece. A device showing the time of day not a striking or chiming mechanism.

Tachymeter Chronograph. Has a calibrated dial so that miles per hour can be seen.

Timing. The regulation of a watch.

Tortoiseshell. Used for covering early watch cases.

Tourbillon. A device for turning the watch escapement to reduce vertical positional errors. by A.L Breguet.

Train. The succession of wheels driving a watch.

Up And Down Dial. A small sub dial indicating the amount of wind in the main spring.

Verge. A recoil friction escapement with a crown escape wheel and pallets set at right angles to the axis of the escape wheel.

Virgule. A form of escapement introduced in 1750 to improve on the verge escapement.

Virgule Double. Similar to the virgule but giving impulse to the balance in both directions.

Volute. The flat portion of the balance spring.