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Below is a glossary of clock terms if you cannot find the term you are looking for please contact me
  Underlined Links in this column are cross references to other entries
Anchor Type of pallet used in escapements of clocks & watches shaped like a ships anchor
Arbor Spindle or axle on which clock wheels are mounted see also Barrel Arbor
Back Cock Small plate mounted on back plate of clock in which the pallet pivots
Back Plate The plate in which the movements back pivots run (the back plate is that which is furthest from the dial)
Balance Oscillating part usually a wheel which controls the timekeeping of clocks & watches
Barrel Cylindrical part which in spring driven clocks holds the mainspring and in weight driven clocks has the lines wrapped around it
Barrel Arbor Spindle with a hook which catches the mainspring and has a square for winding
Beat The beat of a clock is its tick, a clock must be 'in beat' for it to be reliable and a good timekeeper, a clock is in beat when the tick and tock of the clock are at equal intervals
Bezel Metal frame often holding a glass
Bob The weight at the end of the pendulum which is moved up or down in order to regulate the clock
Brocot Escapement Type of dead beat escapement used in many French clocks using semi circular pins in the pallets
Bush A replacement bearing used to repair worn pivot holes
Cannon Pinion Pinion which holds the minute hand usually a friction fit over the centre wheel or loose over centre pipe of a clock in order to allow the minute hand to be moved
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
Centre Wheel Wheel on which the cannon pinion is fitted usually next to the barrel or great wheel depending on the type of clock
Centre Seconds A seconds hand fitted to an arbor pivoted at the centre of the dial usually at the same point as the hour and minute hands
Chapter Ring Circle on a dial which carries the markings for the hour and minutes
Chiming Clock Clock which sounds a tune at each quarter of an hour such westminster,whittington etc.
Chronometer Clock or watch often used on board ship which gives excellent timekeeping
Click Ratchet or pawl used to prevent the mainspring or weight unwinding when wound held in position by the clickspring
Cock Bracket or small plate attached to larger plate to hold parts which are fitted outside the main plates of the clock
Collet Washer used in conjunction with a pin to hold parts such as the minute hand to an arbor
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
Count Wheel Wheel used in striking clocks with 12 slots at different spacings used to stop the strike train after striking the appropriate number
Crown Wheel Escape wheel of a verge escapement transmitting power to the verge pallets
Crutch Part attached to the pallets used to transmit power to the pendulum
Dead Beat Type of Escapement where there is no recoil caused by the swing of the pendulum, George Graham invented one such escapement
Detent A piece which positions and holds another part in position
Dial The visible 'face' of the clock on which the numerals or chapter ring are situated and from which one can tell the time
Drop 1 The free travel of the escape wheel between the impulse and the locking of the pallets
Drop 2 English Dial clock where the pendulum hangs beyond the circle of the dial and is cased below the dial sometimes with a glass aperture to show the brass faced pendulum
Drop3 Distance required for the weights of a clock to fall in the clock's duration
Drum Another term for barrel
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
Dummy Pendulum A small disc seen through a slit in the dial of some clocks attached to the pallets to show the movement of the pendulum
Duration Time over which the clock will run on one winding
Escape Wheel Wheel which transmits power through the pallets to the pendulum
Escapement Term used for the type of parts that transmit power to the pendulum or other device which regulates timekeeping. Such as verge, anchor, dead beat and platform escapements
False Pendulum See Dummy Pendulum
Finial Ornamental piece of turned wood or brass fitted to the top of cases
Foliot Early form of balance using oscillating arms attached to a verge escapement with adjustable weights to regulate timekeeping
Fly or Fly Wheel Vane used to regulate the speed of the striking train using air resistance
Friction Washer Spring washer, used mainly in english clocks to connect the cannon pinion to the centre wheel whilst allowing the minute hand to be moved
Front Plate The clocks main front plate positioned just under the dial
Fusee Cone shaped part usually with grooves to accept a line attached to the barrel, fixed to the great wheel of the clock by a slip washer with the winding ratchet inside. Its purpose is to equalise the torque exerted by the mainspring as the spring runs down, when fully wound the line pulls on the small end of the cone and when unwound the line is at the large end of the cone thus the power applied to the train is more or less the same when it is fully wound as it is at the end of its duration
Gathering Pallet Part of the striking mechanism which gathers one tooth of the rack per strike thus counting number of strikes, sometimes also used to lock the strike train at the completion of striking
Gimbals A type of universal joint used in ships chronometers to keep the movement horizontal
Gong Rod or coil of hard metal such as bronze or hardened steel struck by a hammer during chiming or striking
Grande Sonnerie Striking clock which strikes the last hour and the quarters at each quarter hour
Grandfather Clock Common name given to Longcase clocks
Great Wheel First wheel in the train attached to the barrel or fusee
Gridiron Pendulum Pendulum invented by John Harrison to compensate for changes in temperature,arrangement of steel and brass rods fixed in different positions which expand different amounts keep the pendulum the same length
Hammer Part which is lifted and then released to strike a gong or bell in a striking or chiming clock
Hands The 'pointers' which enable the viewer to tell the time, many different patterns have been designed over the years and can be a good indicator of the age of a clock
Hood The top of a longcase clock which can be removed by pulling forward or sometimes upwards in early clocks
Hoop Wheel Wheel in the striking train of a count wheel clock which a lever stops at the end of the striking
Hour Wheel Wheel on to which the hour hand is fitted sometimes bearing on a seperate cock which holds it away from the cannon pinion over which it is fitted, it is driven by the minute wheel
Impulse The period during which the escape wheel imparts power to the pallets
In Beat See Beat
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 Old form of pinion in which pins are held between 2 discs rather than leaves or teeth cut from the metal of the arbor
Leaf Each tooth of a cut pinion is called a leaf
Lines Lines made of gut or wire are used in both weight driven clocks and fusee clocks
Locking Plate Another term for a count wheel
Longcase Clock Commonly known as a 'Grandfather Clock'
Main Wheel See Great Wheel
Mainspring a long strip of hardened & tempered steel coiled into a barrel or with a loop around a pillar used to give power to the train of a clock
Maintaining Power A device used to provide power to a weight driven or fusee clock during winding, without it there is a possibility of damage to some escapements due to the swinging of the pendulum whilst no power is getting to the escapement
Minute Wheel A wheel in the motion work often with a pin which releases the striking mechanism, driven by the cannon pinion it drives the hour wheel
Mock Pendulum See Dummy Pendulum
Motion Work The mechanism under the dial which keeps the hour and minute hands correctly aligned
Movement The works of a clock or timepiece
Oil Sink Small hollow area concentric with pivot hole in clock plate intended to retain the oil at the pivot
Pallets The part of the escapement which takes power from the escape wheel and delivers it to the pendulum via the crutch with each oscillation of the pendulum or balance
Passing Strike A clock striking just once each hour as the minute hand passes the hour is described as a passing strike clock
Pendulum A rod with weight at the bottom usually suspended at the top by a spring or silk cord, a method of regulation is normally fitted, making the pendulum shorter makes the clock run faster
Pillars Metal pieces which hold the plates together the correct distance apart
Pin Drum A drum with pins protruding which lift hammers in a chiming or musical clock as the drum revolves
Pin Wheel A wheel in the striking train fitted with pins to lift a hammer during striking
Pinion Part of the train with leaves or teeth driven by the wheels of the train
Pivot End of an arbor which revolves in a hole in the plates
Plates Flat metal or occasionally wooden pieces in between which the wheels and other internal parts are fitted
Platform Escapement Consisting of a balance, pallets and escape wheel on a flat brass plate, these are most often found on french clocks in particular carriage clocks
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
Pulley Wheel around which the lines of a weight driven clock run halving the drop required but also halving the force imparted on the train
Push Repeat A mechanism usually on carriage clocks which when a button is pushed repeats the last hour strike
Quarter Chime A train which is activated at each quarter of an hour playing a tune on more than 2 bells or gongs
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 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
Ratchet Wheel Wheel with angled teeth to prevent unwinding when held by the click
Rate The amount by which a clock gains or loses
Rating Nut A nut on a pendulum used to raise or lower a pendulum bob-lower is slower
Recoil The amount the escape wheel is pushed backwards by the swing of the pendulum on a recoil escapement
Regulator 1 A weight driven pendulum clock without a striking train designed for very accurate timekeeping, although so called vienna regulators often have striking trains
Regulator 2 The part of a clock designed to alter the rate of a clock (as in rating nut) but normally associated with balance wheel clocks like carriage clocks
Repeater A clock with a mechanism which when activated repeats the striking of the last hour
Seatboard The board on to which a movement is fixed
Snail A cam like wheel on to which the rack tail drops in order to select the number to strike
Spandrel An ornamental piece fitted to the corner of dials, the designs vary greatly and can help in dating of clocks
Star Wheel A star cut wheel held by a detent to position either a date wheel or a striking snail
Stop Work A mechanism used to prevent a clock from being overwound most commonly found in fusee movements
Strike A hammer hitting a gong or bell counting the hours
Strike-Silent A mechanism which allows the striking train to be turned off without causing damage to the movement
Suspension The piece on which a pendulum hangs, usually a spring but in some older clocks a piece of thread is used
Sweep Seconds See Centre Seconds
Timepiece A clock which does not chime or strike
Ting-Tang A striking clock which sounds the quarters on two tone gongs or bells
Train The wheels and pinions of a clock, the 'going' train keeps the time, also 'striking' & 'chiming' trains are used in more complicated clocks
Verge An early type of escapement, technically the shaft on to which the pallet faces are fitted
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
Weights The weights provide the power for the trains of a clock often made of lead sometimes encased in brass or cast iron
Wheel Circular piece with teeth cut around its circumference fitted on to an arbor these make up the train of a clock