SPONSORED ADVERTISEMENTS

Glossary of Terms: Watches, Watchmaking and Horology

Hairspring
- Also called "Balance Spring." The delicate, spiral-wound spring which governs the oscillation of the balance wheel and provides the fundamental timekeeping mechanism of the watch. Hairsprings can be "flat" or "overcoiled" (also called Breguet) in design. The shape of the overcoil or terminal curve of the hairpspring can have a significant effect on the positional accuracy of the watch. Hairsprings can be made of blue steel or other more exotic metal alloys such as "Invar" or "Elinvar" which are formulated to resist the adverse effects of temperature or magnetism.
Hunter Case
- Sometimes called "hunting-case." A pocket watch which has metal covers on both the front and back of the watch. The lid over the dial is typically released by pressing the winding crown. See also "Cuvette". See our page on how to identify a hunter-case watch.
Horology
- The science of time and time measurement, including clocks and watches.
Hour Wheel
- A flat, toothed wheel mounted on a hollow tube, which fits over the cannon pinion and carries the hour hand.
Impulse Jewel
- The jewel-pin that serves as the point of contact between the time-train and the balance wheel. Also called the roller jewel. Also see our page on the use of jewels in vintage watches.
Jewel
- 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 jeweled". 19-jewel or higher is considered a high-grade watch. The jewels themselves have no value as jewels, and contrary to popular myth, unscrupulous watchmakers will not "steal the jewels out of your watch." Also see our page on the use of jewels in vintage watches.
Karat
- A measure of fineness; 24 karat is fine gold. One karat equals 1/24 (.0417%), so that 14 karats is 14/24 fine gold and the balance 10/24 is alloy. 24K is pure gold. Jewelry is typically made from 18K or 14K gold, which contains other metals for strength. If the gold content of an alloy is less than 10/24 (10K) the object cannot be represented as karat gold. Not to be confused with "Carat" which is a unit of weight used in the measurement of gem-stones.
Lancashire Gauge
- An arcane English system of measurement used for watches. For a more complete description of Lancashire Gauge and a table of watch sizes, click here.
Lever-set
- A watch that is set by moving a small lever usually located under the bezel. A safety feature of Railroad watches that prevented accidental changes to the time. See also "Pendant Set". Also see our page of instructions for setting a lever-set watch.
Lift
- The motion imparted to the pallet during contact with the top lifting faces of the escape wheel teeth.
Ligne
- (French, pronounced "line") A unit of measurement used for (usually) Swiss and French watches. One Ligne is 2.2558291mm or 0.088812168 inches. There are 12 Ligne to one French inch (pouce, French for thumb) and 12 pouce to a French foot (Pied). See also Douzième .
Lugs
- Extensions on both sides of a wristwatch case where the bracelet or strap is attached.

SPONSORED ADVERTISEMENTS