Old Passion's Clock Dictionary
Keyless Rack Clock
See Rack Clock.
A dial on a clock that resembles the shape of a kidney.
A cam with a profile resembling a kidney commonly used for indicating solar time. Mean time and solar time coincide four times a year and differ by as much as 16 minutes at other times. A kidney-shaped cam rotated by the clock's mechanism may be used to drive an additional hand, indicating solar time, and a sundial may then by used to regulate the clock to mean time, without reference to equation tables. Clocks having a hand indicating solar time are known as 'equation clocks'.
A clock frequently of oak, manufactured from the late 1800s to the early 1900s, that was commonly placed on a shelf in a kitchen.
Serrations or other indentations on a metal surface such as a clock hand-set button, designed to improve the grip of the fingers upon it. Knurling is produced by a knurling tool which carries a hardened steel wheel with the desired pattern upon it. This wheel turns on a hardened shaft lying across a slot cut in the holder. The part to be knurled is rotated in the lathe while the tool is pressed hard against it. In mass production, special machine-knurling tools are used.
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