It's a great way to meet other clockmakers.

About 400-day clocks

torsion pendulum clock, anniversary clock,  400-day clock, mechanical torsion pendulum. weighted disk or wheel, decorative wheel with 3 or 4 chrome balls on ornate spokes, suspended by a thin wire or ribbon called a torsion spring (also known as "suspension spring"). The torsion pendulum rotates about the vertical axis of the wire, twisting it, instead of swinging like an ordinary pendulum. The force of the twisting torsion spring reverses the direction of rotation, so the torsion pendulum oscillates slowly, clockwise and counterclockwise. The clock's gears apply a pulse of torque to the top of the torsion spring with each rotation to keep the wheel going. The wheel and torsion spring function similarly to a watch's balance wheel and hairspring, as a harmonic oscillator to control the rate of the clock's hands.Torsion clocks are usually delicate, ornamental, spring-wound mantel clocks. The polished clock mechanism is exposed under a glass case or dome, to allow people to watch the torsion pendulum turn. Clocks of this style, first made by Anton Harder around 1880, are also known as 400-day or anniversary clocks, because many can run for an entire year on a single winding. This does not mean they will keep accurate time the whole year. It's best to wind the clock once a month. But some models will run up to 1000 days on a single winding.Torsion clocks are capable of running much longer between windings than clocks with an ordinary pendulum, because the torsion pendulum rotates slowly and takes little energy. However they are difficult to set up and are usually not as accurate as clocks with ordinary pendulums. One reason is that the oscillation period of the torsion pendulum changes with temperature due to temperature-dependent change in elasticity of the spring. The rate of the clock can be made faster or slower by an adjustment screw mechanism on the torsion pendulum that moves the weight balls in or out from the axis. The closer in the balls are, the smaller the moment of inertia of the torsion pendulum and the faster it will turn, like a spinning ice skater who pulls in her arms. This causes the clock to speed up.One oscillation of the torsion pendulum usually takes 12, 15, or 20 seconds. The escapement mechanism, that changes the rotational motion of the clock's gears to pulses to drive the torsion pendulum, works rather like an anchor escapement. A crutch device at the top of the torsion spring engages a lever with two anchor-shaped arms; the arms in turn alternately engage the teeth of the escape wheel. As the anchor releases a tooth of the escape wheel, the lever, which is fixed to the anchor, moves to one side and, via the crutch, gives a small twist to the top of the torsion spring. This is just enough to keep the oscillation going.The Atmos clock, made by Jaeger Le Coultre, is a type of torsion clock which doesn't need to be wound or powered at all. The mainspring which turns the clock's wheels is kept wound by small changes in atmospheric pressure and/or local temperature, using a bellows mechanism. Thus no winding key or battery is needed, and it can run for years without human intervention.The torsion pendulum was invented by Robert Leslie in 1793. The torsion pendulum clock was first invented and patented by American Aaron Crane in 1841. He made clocks that would run up to one year on a winding. He also attempted to make precision astronomical regulator clocks based on the torsion pendulum, but only four sold.The German Anton Harder apparently independently invented and patented the torsion clock in 1879-1880. He was inspired by watching a hanging chandelier rotate after a servant had turned it to light the candles. He formed the firm Jahresuhrenfabrik ('Year Clock Factory') and designed a clock that would run for a year, but its accuracy was bad

a movement, also known as a caliber or calibre (British English), is the mechanism of a watch or timepiece, as opposed to the case, which encloses and protects the movement, and the face, which displays the time. The term originated with mechanical timepieces, whose clockwork movements are made of many moving parts.

Antique Vintage, Old, Retro, Distressed, MCM, Mid-century Modern, Collectible, Collecting Collection, relic Rustic Historic Memorabilia Rare Classic Early, Authentic, Aged, Ancient, Last , Historical, Bygone Era, Artifact, , Antiquated, Archaic, Rarity, Primitive Valuable, Uncommon, Unique, Prized, One Of A Kind, Hard To Find, Desirable, Exclusive, Only, Sought After, Museum Piece, Souvenir, Curious, Keepsake, Treasure,

clockmakers tools Clockmaker's, Watchmaker's, Collectors,  Dealers Selection