Wheellock

A close modern analogy of the wheellock mechanism is the operation of a lighter, where a toothed steel wheel is spun in contact with a piece of sparking material to ignite the liquid or gaseous fuel.

A sparking material, usually a small piece of iron pyrite, is clamped and held by vise-like jaws at the swinging end of the arm.

The upper segment of the grooved wheel, made of hardened steel, projects through a slot cut to its precise dimensions in the base of the priming pan.

The pan cover may be slid open and closed by hand, but it is also attached to an arm inside the lock plate, which is acted upon by the eccentric on the shaft of the wheel.

The trigger engages one arm of a "z"-shaped sear pivoting in its centre between two upstanding brackets riveted or brazed to the inside of the lockplate.

Finally the dog is pulled back so that the pyrite in its jaws is resting on the top of the pan cover, under some pressure from the spring at the toe of its arm.

The fast rotation of the wheel against the pyrites produces white-hot sparks that ignite the powder in the pan, which is transferred to the main charge in the breech of the barrel via the vent, and the gun discharges.

[2][3][4] In 1517 and 1518, the first gun control laws banning the wheellock were proclaimed by the Emperor Maximilian I, initially in Austria and later throughout the Holy Roman Empire.

[citation needed] As Lisa Jardine[5] relates in her account of the assassination of William the Silent of the Netherlands, in 1584, the small size, ease of concealment and user-friendly loading aspect of the wheellock, compared to larger and more cumbersome hand-held weapons, meant that it was used for the killing of public figures, such as Francis, Duke of Guise and William himself.

Jardine also argues that a stray wheellock pistol shot may have been responsible for the St. Bartholomew's Day massacre of French Huguenots in 1572.

[6] Among the advantages of the wheellock was a better resistance to rain or damp conditions than the matchlock and the absence of a telltale glow, or smell from the burning slow match, itself a hazard in proximity to gunpowder.

A slow match could be next to impossible to light in rain, but the wheellock allowed sparks to be generated in any weather, and the priming pan was fitted with a cover that was not opened until the instant the gun was fired.

A highly skilled gunsmith was required to build the mechanism, and the variety of parts and complex design made it liable to malfunction if it was not carefully maintained.

The wheellock mechanism however gave faster ignition than the flintlock, because the sparks were produced directly in the pan rather than having to fall a certain distance from the frizzen.