A

Abacus

The uppermost member of the capital of a column.

Action

A term used to denote the extent of the arc of vibration of the balance, or pendulum.

Addendum

The portion of a gear wheel tooth ot pinion leaf that is external to the pitch circle.

Aiguille

French for watch or clock hand.

Albert

A watch chain, used as a means of attaching a pocket watch to a garment. Named after albert, Prince Consort.

Aloxite

A grinding stone used with oil which is similar to a India Oil Stone.

Anchor

Type of pallet used in escapements of clocks & watches shaped like a ships anchor.

Annealing

A process of heat treatment for reducing the degree of metal to give it maximum malleability or ductility.

Arkansas Stone

A fine grained, hard, whitish stone ( Silicon) used for whetting tools to a fine edge.

Ayr-Stone

A bluish-gray stone used with water to make a paste to add a finish to brass or other soft metals.

B

Back Cock

The pallet cock of a pendulum clock. The term applies to both Anchor and Crown Wheel escapement clocks.

Back Plate

The plate in which the movements back pivots run (the back plate is that which is furthest from the dial)

Backlash

The circumferential clearance between mating teeth.

Backslope

The part of the balance staff which tapers from the balance on the underside: also refers to the cut at the back of a balance staff pivot.

Banking

When applied to the lever escapement, it is that part on which the lever rests or "banks".

Barograph

An instrument which records changes in atmospheric pressure.

Belfrey

The hood of a tall case clock in which the movement is cased.

Bench Wheel

A large grooved wheel fitted with a handle and mounted on a bracket or stand, fixed to the workbench in a suitable position for driving turning tools or lathes by means of an endless cord. The bench wheel remains fixed in one place while the turning tools are vice-held. The bench-wheel bracket usually has a sliding adjustment for tensioning the cord.

Biseau

A bevel. In Horology it refers to the plates of a watch movement which have been bevelled to make the movement thin on the edge: a biseau movemnt.

Blowpipe

A long tapered metal tube through which air is blown by mouth or bellows to increase the heat of a flame and to direct it on to the point where it is needed when brazing or soldering.

Bread

Bread was used by the old English finishers as a means of cleaning the work during polishing. It is more efficacious than pith. The center portion of a piece of bread, without the crust, about the size of a golf ball was kneaded up with oil to the consistency of putty and used by dabbing on to the work.

Bridge

A bracket with two feet commonly used to support the pivot of an arbor outside the plates of a clock.

Bulls Eye Door

A circular orifice in Tall Case clock doors. It permits the view of the pendulum swing.

Butterfly

A cutout in the plate of a pocketwatch. This allowed for easier adjustment of the escapement. This design was utilized by the U. S. Watch Co.

C

Cadrature

Another term for motion work, the mechanism lying immediately behind the dial outside the fromt plate, transmitting the rotation of the movement to the hands.
The term may also include parts of the striking, calendar or alarm work, if these are external to the plates.

Calotte

A type of watch case which fits into a folding case; also know as a "Portfolio". The outer case, usually made of leather, is the portfolio and the time-piece and its metal case is the Calotte.

Carriage Clock

Type of clock fitted with a platform escapement to enable it to be moved without the problems of putting the clock in-beat usually in a gilded brass case with glass panels all round.

Catgut

The line used to carry the weights of a clock. It is also used to convey the drive from the barrel to the fusee.

Chamber Clock

The name given to the iron Lantern clock prior to the introduction of the pendulum.

Channelling

An operation where grooves are cut into woodwork to form a pattern.

Chapter Ring

Circle on a dial which carries the markings for the hour and minutes .

Chariot

The plate of a cylinder escapement which has the balance and cock attached. This allows the balance and cylinder to be adjusted uniformly.

Cheeks

The part of a long case clock upon which the Seat board rests.

Chops

A term for pieces of wood or soft metal used to protect work held in a vise. These are also known as "Clams".

Civil Time

Two 12 hour periods starting at midnight.

Clock

A device other than a WATCH for indicating or measuring time chiefly consisting of a train of wheels actuated by various devices (as falling weights, a tensed spring, changes in temperature, or electrical impulses), regulated through an escapement in various ways (as by a pendulum, dripping water, a synchronized electrical motor, or the vibrations of atoms), and indicating time most commonly by means of hands moving on a dial often with accompaning bells made to strike at regular intervals (as once each hour) - Webster's Third New International Dictionary, printed 1966.

Cock

A single ended bridge used to house the jewel for one end of the Balance Staff.

Contrate Wheel

Wheel where the teeth are at right angles to the plane of the wheel to transmit the power of the clock train through 90 degrees used in verge escapement clocks and carriage clocks.

Corn Tongs

Tweezers used by jewelers and precious stone dealers for handling stones.

Counterpoise

A method of counter balancing. A weight attached to the hour or minute arbor of a turret clock to counter balance the weight of a heavy hand.

Crocus

A iron oxide used in polishing brass or steel. Rouge is a refined grade of crocus.

Crossings

A clockmaker term for the spokes of a wheel. Good quality clocks usually have 5 or more "crossings" in their wheels.

Crutch

The part attached to the pallets used to transmit power to the pendulum

Cuvette

The dust cap for a watch.

D

Daily Rate

The amount that a clock or watch gains or loses on correct time. A gaining rate is shown as +, and a losing rate is shown as -.

Depth

The degree of intersection of a pair of gears. The depth is correct when the pitch circles meet.

Detent

A piece which positions and holds another part in position.

Diamantine

A white powder that when mixed with a small amount of oil is used for finishing and polishing steel.

Dielectric

An insulating material or substance capable of supporting an electrical stress. Some examples would be mica, waxed paper, glass, etc.

Dogs

The clamps or fixing pieces found on the face plate of the mandrel, uprighting tool, etc. ( see mandrel)

Draw Plate

A plate with a series of graduated holes. It is used to reduce or draw down the diameter of round wire.

Dummy Blow

Grande sonnerie clocks have a silent strike where both hammers are held clear of the gongs this happens after the hours have been struck and before the quarters are struck.

Duration

Time over which the clock will run on one winding .

E

Ebauche

An unfinished movement, i.e. the movement in the rough before the escapement is fitted, or the train has been pivoted.

Ebonized

Having a black finish that looks like ebony wood.

Electromagnet

A magnet, the properties of which are exhibited under and dependent upon, the engergizing influence of an electric current.

En Plien

A term used to describe antique watches that are fully crowded with jewels, pearls, etc.

Endstone

The jewell disc fitted to form the end of a hole, so that the end of the pivot can work upon it whereas without it, the shoulder of the pivot would take the weight or thrust. Ocassionally this is referred to as Jewel Cap, or endpiece..

Epact

The age of the moon on 1st January in any year; when this is known its age at any subsequent date in the year can be deduced. Since twelve lunations equal 354-36 days and a year equals 365.24 days, the epact increases by a little under eleven days from year to year, with a backward step of 29 1/2 days each time it passes this figure

Erg

A unit of work or energy.

F

Facing

The process of finishing the ends of pinion heads.

Festoon

Also known as Swag. It is a decoration which is a curved or draped form.

Filigree

Ornamental work made from wire

Flank

The side of the wheel tooth or pinion leaf which is engaged during contact.

Flirt

A weighted or spring loaded lever which is wound by the going train and released to let off strike work.

Fly

The governor or onroller of the speed of thr\e strike or chime train.

Fraise

Also called a Ingold Fraise. it is a type of cutter used in correcting the form of wheel teeeth. It is now know as either a Rounding-up or Topping Tool Cutter.

Fret

Refers to pierced wood or metal used in clock cases to allow the sound to be emitted.

Friction Washer

A spring washer, used to connect the cannon pinion to the center wheel while allowing the minute hand to be moved

Frosting

The granular or matted finish given to a surface of brass clock parts prior to gilding.

G

Gadroon

A decoration resembling reeds or inverted flutes.

Gallows Tool

A tool used in clockmaking. It is used to hold pinions while the leaves are being shaped

Garter Back

A term that refers to the termination of engine turning employed on watch cases.

Gilding

The process of coating a base metal such as brass with a very fine layer of gold, much used in watch-movement finishing. For clocks, it is mostly used to decorate external details.

Gimbel

A device used in Marine Chronometer boxes to hold the movement horizontal no matter how a ship might roll or pitch.

Gnomon

The pointer of a sundial which casts the shadow.

Graver

A cutting tool of hardened steel, square or lozengeshaped in section and of varying thickness. One end has a tang for fitting into a ahndle and the other is ground off at an angle to obtain the cutting point or face.

H

Hard Core

A term referring to the hard packed dirt and/or rust sometimes found in pinion leaves and the corners of pin pallet escape wheel teeth.

Hipp-toggle

A mechanism developed by Matthew Hipp. The purpose is to maintain a pendulum in oscillation electrically.

Hob

A type of milling cutter use in the manufacture of wheels and pinions.

Hobbing

The process of cutting wheels and pinions. A machine using a hob drives both the cutter and blank at the same speed and feeds them closer together as the cutting progesses.

Hoop Wheel

A wheel in the striking train of an old type of clock. It has a brass edge or "hoop" attached to the side, extending about 7/8th of the circumference, and acts as the locking device for the striking train.

Horns

The part of the lever, in the lever escapement, which forms the ears of the notch.

Horse

A stand or bracket used to hold a clock movement while testing outside of the case.

I

Impulse

The period during which the escape wheel imparts power to the pallets.

In The White

A term that refers to any type of wood, irrespective of color, before it is polished or treated in another fashion.

Incabloc

A shock resisting system where the jewel holes and endstones of the balance "give" when the watch receives a shock. the spring like settings operate until a shoulder turned on the balance staff contacts a block and so takes the effect of a major shock.

Incastar

A system of regulating by lengthening or shortening the balance spring.

J

Jacot Drum

An accessory used in a lathe for the purpose of polishin pivots.

Jewelled

A term used in horology to define bearings or holes and surfaces made from jewel stones.

K

Kerf

A cut made by a saw, sometimes used as a form of decoration. Similar to some form of inlay work but without the inlay.

L

Lantern Clock

Early weight driven 30 hour clock with brass case with 4 posts at the corners and bell at the top, with a verge escapement and in the earliest clocks a balance wheel foliot later with a pendulum made c.1630-1730.

Lantern Pinion

A squirel cage rotor with leaves to transfer power from one arbor to the next.

M

Maintaining Power

A mechanism for maintaining a clocks drive while winding.

Mandrel

A faceplate fitted with "dogs" or clips to hold the work during turning, fitted to the lathe. or as a seperate self contained tool. In engineering, a mandrel is a bar set between centers to mount tools or work.

Motion Work

The mechanism under the dial which keeps the hour and minute hands correctly aligned

N

Niello

A form of semi-hard black decoration use on watch cases, usually silver. The design is deeply engraved and filled with a lead-oxide compound which provides a black pattern similar to inlay.

O

Ogee

A moulding: convex above and concave below, a continous curve.

Oil Sink

Small hollow area concentric with pivot hole in clock plate intended to retain the oil at the pivot.

P

Parting Out

The practice of taking a watch, original or not, and disassembling it, including, but not limited to, the case, the movement, dial, hand, and other components of the "watch" and selling the various components to profit over and above the value of the watch to "switchers", who to their liking by mixing and matching various movements, dials and cases to upgrade or improve the condition of their watch.

Passing Strike

A clock striking just once each hour as the minute hand passes the hour is described as a passing strike clock.

Pawl

A device mounted on a oscillating arm used to advance a ratchet. Commonly known as a "click".

Pillars

Metal pieces which hold the plates together the correct distance apart.

Pitch Circle

The cicle drawn from the center of a toothed wheel upon which the construction of the curve of the tooth is formed.

Platform

A plate carrying a subassembly which may be removed for work without disturbing the main frame of the clock.

Platform Escapement

This type of escapement consists of a balance, pallets and escape wheel on a flat brass plate, these are most often found on french clocks in particular carriage clocks

Plinth

The lower part of a clock case upon which the case is built, also termed the base.

Potance

Bracket or cock which carries the lower pivot of the crown wheel of a verge movement.

Pull Repeat

A mechanism which when a cord is pulled repeats the last hour strike or quarters of a seperate chiming train.

Push Repeat

A mechanism usually on carriage clocks which when a button is pushed repeats the last hour strike.

R

Rack

Part of the striking mechanism with teeth which are counted by the gathering pallet and a tail which falls on to the snail selecting the number to be struck, invented in1676

Rack Hook

The piece which holds the rack in position between strikes until the next tooth is picked up by the gathering pallet and which holds the rack in position when striking is completed

Rating Nut

A nut on a pendulum used to raise or lower a pendulum bob-lower is slower

Recital Alarm Clock

An eight day alarm clock which repeats the alarm every 24 hours without resetting.

Remontoire

A device used in higher quality clocks, which winds an auxiliary spring or weight. This winds the clock at shorter intervals to provide a more constant driving force for the escapement.

S

Seatboard

The board on to which a movement is fixed

Shrouds

The caps or ends of the lantern pinion into which the pins or trundles are fitted.

Snailing

A process which imparts a decorative finish to metal clock parts. The finish takes the form of curved lines begging from a common center,

Spandrel

An ornamental piece fitted to the corner of dials, the designs vary greatly and can help in dating of clocks.

Stopwork

The mechanism used to limit the number of turns, either up or down, of a mainspring.

Striking Jack

Earlier types of Turret or Tower clocks were not fitted with dials or hands, they just struck the hours. At a latter time figures of men, known as jacks, jacomarts, or striking jacks were added to the outside to strike hours on bells. This dates back to the latter part of the 14th century. During the 15th and 16th centuries, dials and hands were added.

Switching

1. Robbing parts from one watch to improve another for ego, money/greed or bragging rights.
2. Purist collectors loathe this practice as it destroys the credibility and originality of watches!
3. Help maintain ethics in horology--don't part out or switch!

T

Tea-Time Clock

A type of alarm clock incorporated into a fixture with a specially designed electric kettle and a tea pot. At a predetermined time, the kettle is made to boil and pour the water into the tea pot. It is also called a "Teasmade".

Tempering

Tempering is the process of reducing the hardness or brittleness of a metal or alloy.

Throw

A lathe like device typically used by clockmakers. It had a large hand operated wheel attached to a bracket at the base. From this wheel a length of catgut ran to a smaller pulley. The large wheel would then be hand cranked which turned the work.

Time

a:A moment, hour, day or year as indicated by a clock or calendar. b: Any of various systems ( sidreal or solar) of reckoning time.

Ting-Tang

A striking clock which sounds the quarters on two tone gongs or bells.

Toller

A single strike of a bell.

Trundles

The wire "leaves" of a Lantern pinion.

Tympanum

The arched section over the dial of a clock.

U

Unlocking

The act of releasing. In horology, it is a term to define the release of a part or mechanism previously locked or inopereative. It is generally used in reference to the unlocking of the escape wheel, sometimes referred to as "discharging".

V

Vein

A fine break or crack that shows in a enamelled dial as a thread-like line. This is often invisible when thoroughly and properly cleaned.

Volute

Spiral. In relation to horology, it is associated with the "flat" balance spring. when an overcoil is provided, the flat portion of the spring is referred to as the "volute.

W

Wag-On-The-Wall Clock

An American term for a wall clock in which the pendulum and weights are exposed to view.

Wagon Spring

A series of flat springs used instead of a coil spring to power a clock movement. attributed to Joseph Ives of Bristol Connecticut

Warning

A few minutes before the hour many striking mechanisms lift a warning piece which lifts the rack hook, allowing the rack to fall on to the snail and letting the strike train to run, until the pin on the warning wheel is stopped by the warning piece, at the hour the warning lever drops of the lifting pin on the minute wheel and allows the striking train to run

Wig-Wag Tool

A tool so devised that a reciprocating or backward and forward motion is obtained; used for polishing pivots.

Wings

The appendages on the sides of early clocks. These were used to hide the wide swing of a bob pendulum.

Winker

An iron statue clock with blinking eyes

Z

Zappler Clock

A small pendulum clock made in Austria, in the early 19th century. the short light pendulum swings in front of the dial. Sometimes there are two pendulums swinging in opposite directions.

Zebrawood

A striped, straw-colored African wood that is sliced into veneers to cover an unattractive wood; also called zebrano

Zinc Block

A section of zinc plate, usually 3" x 2" x 1/4" thick. It is used with diamantine for polishing steel parts.