The Column Wheel
The column wheel, as the name implies, is a small fluted column located inside a watch movement. Various “fingers” connected to levers controlling the start, stop, reset and even fly-back functions of a chronograph rest on this column. Each time the column wheel rotates, these varying fingers either drop into the space between flutes or are lifted up by the flutes. Correspondingly, this activates the varying different functions of the chronograph.
To illustrate how the column wheel chronograph functions, let’s first label the important parts of the movement. These parts are usually found on the top of the base calibre when viewing the watch from the back.