Even the simplest of antique watches will contain hundreds of parts. Each component has a critical part to play in the time keeping process. The key components are described in the glossary below.
An Albert is a chain attached to a pocket watch that secures it to a waistcoat button-hole or lapel button-hole with a T-bar. A Double Albert has two chains extending from the T-bar. The pocket watch goes on one end of the chain and sits in the left-hand waistcoat pocket. The other end of the chain will hold a fob, a winding key or a cigar cutter and will be placed in the right-hand waistcoat pocket. The Albert is presumed to be named after Prince Albert, the husband of Queen Victoria.
Ancre is a French word which translates to anchor and indicates that the watch movement is equipped with a lever escapement.
An axle that holds, turns, or supports a rotating component of the movement, such as the barrel.
The balance staff is the centre shaft or axle on the balance wheel. Each end has a “pivot”, which is a very thin point that the balance wheel rides on. The pivots are supported by the balance jewels.
The balance is a weighted wheel that rotates back and forth, being returned toward its centre position by the balance spring. It is driven by the escapement, which transforms the rotating motion of the watch gear train into impulses delivered to the balance wheel.
A barrel is a cylindrical metal box closed by a cover, surrounded by a ring of geared teeth. It contains a spiral spring called the mainspring, which provides power to run the timepiece.
The bezel is a part of the watch’s outer case, it is not considered part of the movement. It is the metal “frame” that holds the crystal in place on the watch. On a pocket watch, the bezel is almost always circular, but on wristwatches, the bezel can be almost any shape. Most open-face pocket watches have screw-on or hinged bezels, while most hunter-case pocket watches have “snap-on” bezels.
Bluing steel is a process that tempers the steel and creates a protective oxidised coating that helps to prevent watch hands from rusting. First, the steel hands are cleaned and polished. Next, the hands are heated, over a bed of brass filings, to a high temperature. The layer of brass filings is used to maintain a stable temperature exchange. The steel changes colour from gold to brown and then purple before it settles to blue.
The loop at the top of the stem over the crown which is used to clip an Albert chain to the watch. The bow is considered to be part of the case, not the movement.
A complementary part fixed to the main plate to form the frame of a watch movement. A bridge spans across an area of the movement and is attached at to the movement plate at both ends.
The case is the metal housing that contains the movement of the watch. The case can be made from almost any type of metal. Many antique pocket watch cases are brass or base-metal plated with gold. The case comes in two main types of design, open-face and hunter.
The chapter ring is the outer part of the dial that marks the hours and the minutes.
A chronometer is a specific type of mechanical timepiece tested and certified to meet certain precision standards. A marine chronometer is used for celestial navigation and determination of longitude. The first practical marine chronometer was invented by John Harrison in 1730. This was the first of a series of chronometers that enabled accurate marine navigation.
A collet (collar) is a metal band used to hold the end of the hairspring to the balance staff.
The knob at the end of the stem, which is used for winding the watch and setting the time.
The glass piece that protects the dial and hands. The crystal can be made from glass, sapphire or acrylic crystal.
The cuvette is a second cover inside of the case back of an antique pocket watch, which provides additional protection as a dust cover. It may be engraved with inscriptions or the maker’s branding. In English, it is called the dust cover.
The “face” of the watch. The dial is most commonly made of metal, or glass-like vitreous enamel on a metal base. The dial usually marked with numbers (or indices, batons & bars) to divide the 360 degrees into hours and minutes, sub-dials showing additional information are called registers.
A movement with a double roller is more robust than one with a single roller. A double roller has a safety feature consisting of a guard pin positioned to engage a smaller roller located below the primary roller table. This arrangement locks the lever in place until the impulse jewel returns to the pallet fork. A single roller doesn’t include this feature and the lever could be moved out of position by a sudden jolt, stopping the movement. A double roller is known as a double plateau in French.
An ebauche is a basic or blank movement often purchased by a watchmaker from an external manufacturer and then modified and branded.
The escapement is the component of the movement that allows the power of the mainspring to be regulated. It allows the power to “escape” slowly and in a regulated fashion, thus keeping time.
A device intended to reduce the effects of uneven power as the mainspring winds down. The mainspring barrel is connected to the fusee, a conical intermediate wheel, with a tiny chain. The fusee is connected to the gear train. When the mainspring is fully wound, most of the chain is wound around the fusee all the way to the narrow end of the cone. As the watch runs, the chain unwinds down to the wide end of the fusee cone as the chain wraps around the mainspring barrel. This has the effect of equalizing the power transmitted to the gear train, because the lever arm of the chain pulling the fusee is shorter when the mainspring is fully wound, and longer when the mainspring is unwound.
Gear Train / Wheel Train
The gear train is the interconnected system of gears and pinions which transmits power from the mainspring to the escapement.
An alternative name for the crystal. The crystal can be made from glass, sapphire or acrylic crystal.
This is the arrangement of the mainspring barrel so that the barrel arbor is turned to wind the watch, and the barrel itself turns as the spring unwinds. The power is transferred to the gear-train is by the engagement of the teeth on the barrel rim and the pinion of the centre wheel. This arrangement means there is always tension on the mainspring, even during winding, so the gear train keeps “going.
A repetitive decorative engraving technique used on dials and cases.
The delicate, spiral-wound spring which governs the oscillation of the balance wheel and provides the fundamental timekeeping mechanism of the watch. The Hairspring performs the same role as a pendulum in a clock.
Half Hunter (Demi-Hunter) Case
A hunter-case pocket watch with a circular window cut in the lid covering the dial which allows the time to be read through the window, without opening the watch. The lid often has the hours engraved or pressed into the metal to make reading the time easier.
The study of the measurement of time, which includes clocks and antique watches.
A watch with a front cover or sprung lid to protect the crystal and dial. The lid is usually sprung and released by pressing the crown on the stem.
Isochronism is derived from Greek roots (iso & chronos) and means, literally, “in the same time.”. A pocket watch is a machine for counting swings of an oscillator. If the oscillation is not consistent then it is impossible to keep accurate time. Therefore, a watch must be isochronous in order to be accurate.
A tiny “bearing” that supports (or caps) a wheel pivot to reduce friction, or is otherwise used to reduce friction and provide a smooth, hard bearing surface within the mechanism of the watch. Usually made of synthetic ruby or synthetic sapphire. In general, the higher the jewel count, the higher the grade of the watch. A 17-jewel watch is considered “fully jewelled”. 19-jewel or higher is considered a high-grade watch. The jewels themselves have no value as precious stones.
A watch that is set by moving a small lever usually located under the bezel. This is a safety feature of railroad pocket watches that prevented accidental changes to the time.
A traditional measurement of length used by Swiss watchmakers to describe the size of the movement. A ligne (pronounced lines) is 1/12 of an old French inch, which is about 2.256mm. It wasn’t used as a precise measurement as typically, manufacturers would round up or down to the nearest half ligne. For example, a 42mm movement would be rounded up from 18.5 to 19 lignes.
Extensions on the sides of a wristwatch case where the bracelet or strap is attached.
Mainspring & Mainspring Barrel
The wound, flat metal spring which provides the motive power for the watch. Older mainsprings were “blue steel,” but more modern mainsprings tend to be made of alloys which are more resistant to breakage and corrosion.
A marriage watch is a term used to refer to the union (or marriage) of a modern case with an antique watch movement, usually antique pocket watch movements. In essence, it is a pocket watch converted into a wristwatch, combining an antique movement with other original parts and/or non-original parts.
A movement based on a mainspring which when wound slowly unwinds the spring in an even motion to provide accurate timekeeping. Many movements are purchased as “Ebauche” by watchmakers and then refined.
The glass transparent covering (crystal) of the watch dial. Can be glass, sapphire or acrylic.
A composition of nickel, copper and zinc often used in vintage watch cases. It contains no silver. Also known as German Silver.
A pocket watch with no lid or metal cover for the crystal and dial.
The geared arbor of a wheel which is “pushed” by a larger wheel.
The power reserve is the amount of time the watch can run after being fully wound.
A sub-dial on the main dial, usually showing the seconds, but can show other complications such as the date or moon phase.
Part of the balance mechanism used to make fine timekeeping adjustments. The regulator usually has 2 vertical pins which straddle the hairspring and can be adjusted to make the effective length of the spring longer or shorter, resulting in changes to the rate of the watch. Typically, the regulator will be marked “Fast” and “Slow”, or “Advance” and “Retard”.
A watch with a striking complication that chimes the hours and quarters.
A reversing pinion is an invention designed to prevent damage to the movement in the event of a mainspring breakage. Instead of the centre wheel pinion being fixed to the staff it is screwed on. In normal use the gear teeth on the mainspring barrel bear against the pinion and keep it screwed down. If the pressure is suddenly reversed the pinion unscrews and the power dissipates harmlessly without passing through the gear train.
A very hard and transparent synthetic form of sapphire used as a watch glass or crystal. Sapphire is highly scratch-resistant with a value of 9 on the Mohs scale of mineral hardness. As a comparison, diamond has a value of 10.
This is a pocket watch where the stem emerges from the watch at 3:00 rather than at 12:00. This is most common with hunter-cases because it makes the time easier to read when you open a hunter, as you hold it in your right hand and press the stem with your thumb to open the lid. 12:00 ends up naturally in the correct position at the top of the dial.
The shaft that sticks out of your pocket watch with the crown on the top, used for winding the watch and setting the time. A button is often found at the top of the stem to open the case back for key wound watches or for opening the front cover on hunter cased watches.
An alternative name for a register.
A “sunk dial” on a pocket watch refers to the layering of various sections of the dial to create a more polished end product. Typically, the two areas of the dial that were “sunk” were the centre (inside the chapter ring) and the seconds sub-dial. A single-sunk dial usually just had the seconds-dial recessed, and a double-sunk dial usually had the centre and seconds sub-dial recessed. The sunk seconds sub-dial also serves the purpose of allowing the second hand to sit a little lower. Sunk dials are generally found on higher-quality watches due to the extra work and materials required to make them.
A complication designed to eliminate or substantially reduce positional timing errors due to the effects of gravity or unbalanced friction. The invention consists of mounting the entire escapement on a mobile carriage which rotates on its axis within a given time period. Since any positional errors are reproduced at regular intervals, they tend to cancel each other out. The tourbillon was first developed in the 1790s and was typically a feature of high-end pocket watches.
The larger gears in a watch which are often spoked. Solid smaller gears are called pinions.
An alternative name for the crown.