Alarm: A timepiece that can be set to a predetermine time to produce an alarm sound.
Analog: Describes a timepiece with a face-dial and hands. Analog
Arabic Numbers: Are the ten digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9). They are descended from the Hindu-Arabic numeral system developed by Indian mathematicians, in which a sequence of numerals such as "975" is read as a whole number. The Indian numerals were adopted by the Persian mathematicians in India, and passed on to the Arabs further west. They were transmitted to Europe in the Middle Ages. The use of Arabic numerals spread around the world through European trade, books and colonialism. Today they are the most common symbolic representation of numbers in the world (Source: Wikipedia.org). Arabic Numbers Arabic Numbers
Arbor: Is a general term used for a watch part describing an axle used for any gear wheel or winding wheel Arbor
Autowind: A self-winding watch using an oscillating weight, rotor, or solar power. Also can be refered to as automatic winding or autowinding watches.
Balance: Desribes the wheel which works in conjunction with the balance spring to control the watch escapement. Balance
Barrel: The container where the mainspring is coiled. Barrel Barrel
Barrel Arbor: The arbor or axle which the mainspring is coiled around. Barrel Arbor
Bezel: A ring or frame holding the crystal in place. Bezel
Bow: The part of the watch case a chain can be attached. Bow
Bridge: Contains the bearings for the wheel pivots. Usually there will be pilars at each ends. Bridge
Calendar: A watch feature showing the date or day of the week. Some watches show day, month, and year. Calendar
Caliber: Term used to describe the size of a movement.
Cannon Pinion: Thin shaft with pinion leaves at one end carrying the hour, minute and second hands. Cannon Pinion Cannon Pinion
Cap Jewel: The Jewel which rests the pivot end of a gear or other watch movement. Also referred to as a watch movement jewel. Cap Jewel
Case: The container holding the watch movement. Case
Case Screws: The small screws holding the movement inside the case. Watches will usually have two to four screws holding the watch in place. Case Screws
Center Wheel: Describes the while usually at the center of the movement (depends on the manufacturer). Also know as the 'second wheel'. Center Wheel
Click: The part of the watch movement (pawl) to prevent the ratcheting wheel from turning back while the mainspring is being wound. Click
Crown: The watch part at the top of the stem used for winding or setting the watch time. Crown
Crystal: Thee glass or plastic covering protecting the watch face and hands. Crystal
Demi-hunter: Watch cover which has an opening allowing the viewer to see the time. Also referred to as a Demi Watch. Demi-hunter
Dial: Face of a timepiece. A watch may contain multiple dial (known as sunken dials) to provide functions such displaying seconds or date. Dial
Digital: A timepiece where the time is displayed with digits and not with hands pointing to the numbers. Digital
Double Roller: Contains the roller jewel. Double Roller
Double Sunk Dial: Is a watch face containing two dials where a second dials is usually smaller than the main dial face. Double Sunk Dial
Escape Wheel: Usually the last wheel in the watch escapement. It is the wheel giving impulse to the controlling part of the the watch mechanism. Escape Wheel
Escapement: The mechanism of the watch allowing the power of the mainspring to escape - Consisting of three main parts: Balance, pallet, and escape wheel. Escapement
Fourth Wheel: Usually the mechanism or wheel the second hand is mounted on. Fourth Wheel
Full Plate: The top plate which covers the movement, balance, and bridge. Full Plate
Fusee: A cone-shaped pulley with a spiral groove, used in a cord- or chain-winding clock to maintain even travel in the timekeeping mechanism as the force of the mainspring lessens during unwinding. Fusee
Gold Filled: Usually consists of three layers. A thin layer of gold, then a layer of a base metal (usually nickle), and then another thin layer of gold fused together.
Hairspring: The thin spiral spring attached to the balance. Provides the gear drive energy of the watch. Hairspring
Horology: The study and science of keeping or measuring time.
Hour Wheel: The gear or wheel with a shaft coving the cannon pinion supporting the hour hand. Hour Wheel
Hunting Case: Type of watch case which covers the front of the case or watch crystal. Hunting Case
Impulse Pin: The ruby pin (4) in the impulse roller mounted on the balance staff in a lever escapement. Impulse Pin
Impulse Roller: The steel disc (1) mounted on the balance staff of a lever or chronometer escapement clock and carrying the impulse pin or impulse pallet. Impulse Roller
Lever: 1) The pallet or 2) the small lever, when pull out, used to set the watch time or date. Photo is of the Pallet or Lever Lever
Lever-set: The small lever, when pull out, used to set the watch time or date Lever-set
Mainspring: A coiled wire that provides the principal tension or driving power to keep the movement running in a spring-driven clock. Mainspring
Minute Repeater: A watch which can additionally tell the time, at the push of a button or move of a small slide on the side of the case, by striking the hours, quarter hours and minutes since the last quarter hour on small goings inside the watch. Minute Repeater
Minute Wheel Jewel: The jewel which holds the minute wheel in place. Minute Wheel Jewel
Moon Dial: A dial on a watch or clock representing the phase of the moon. Also known as a Moon Phase. Moon Dial
NOS: New Old Stock. A watch or clock or a part that was never used - like new. Usually NOS referes to a timepiece or part that are no longer produced by the manufacturer or the manufacturer produced the product many years ago. NOS
Open Face: Watch face without a cover. Open Face
Overbanking: A malfunction in which the escape wheel unlocks prematurely, without the fork contacting the roller jewel.
Overcoil: A Breguet type of hairspring. Overcoil Overcoil
Pallet: The jeweled lever which works in conjunction with the escape wheel. Pallet
Pillar Plate: The main plate of a watch. Pillar Plate
Pinion: A small arbor gear driven by a larger gear. Pinion
Pivot: The end or point of a moving axle or arbor.
Regulator: The timekeeping rate of a watch depends upon the rate of oscillation of the balance (wheel). The regulator on a watch is a device used to set that rate of oscillation of the balance (wheel). The balance (wheel), the wheel that spins back and forth rapidly, which is a watch's timekeeper, owes its oscillations to the action of the hairspring. The hairspring is located within the balance (wheel) on the balance staff. The regulator functions by having two pins that straddle the end of the hairspring. As the regulator is slightly rotated, the two pins slide along the length of the hairspring by a short amount. The pins thus change the effective length of the hairspring, changing the rate of oscillation of the balance (wheel). However, the regulator can only change the timekeeping rate of the watch by several minutes per day, at best. If a watch has five minutes error per day, or more, it is an indication that the watch requires service. Watches of lesser quality have a simple pointer, whose tip extends over a scale(source NAWCC). Regulator Regulator
Repeater: A timepiece which audibly chimes the hours and often minutes at the press of a button. There are several types of repeaters:
  • Hourly Repeater
  • Quater Repeater
  • Half-quarter Repeater
  • Five-Minute Repeater
  • Minute Repeater
Roller Jewel: The jewel mounted or seated in the roller table, which receives the impulse from the pallet fork Roller Jewel
Safety Roller: (2) The cylindrical metal piece mounted on the balance staff and carrying the impulse pin Safety Roller
Timing: An adjustment mechanizm for setting the timing of a watch in order for the watch to keep accurate time. Also know as the 'Position Timing' Timing
Watch Beat: The correct ticketing or movement of the watch's escapement. Also referred to as the 'beat'.