Barrel (horology)
From Wikipedia, the free encyclopedia
In watchmaking, a barrel is a wheel composed of a toothed disc and a cylindrical box closed by a cover. The barrel turns freely on an arbor and contains a spring such as the mainspring. The spring is hooked to the barrel at its outer end and to the arbor at its inner end. The barrel meshes with the first pinion of the train of a watch. Barrels rotate slowly: for a watch mainspring barrel, the rate of rotation may vary (based on the design) between one ninth and one sixth of a revolution per hour.
- Hanging Barrel: i.e. fixed to the movement only by its upper portion, under a bar
- Plain Barrel: i.e. without teeth, used in fusee watches; the chain, or catgut, was coiled round the plain barrel, connecting it to the fusee.
