Column Wheel

Definition

The castellated wheel that controls a chronograph's start, stop and reset. Each press of the pusher turns it one step, and the chronograph's levers ride onto its teeth or drop into the gaps in a fixed sequence. It is machined and hand-adjusted, and it gives the pusher a short, even, precise click; the cheaper alternative is a stamped cam, which the Valjoux 7750 family uses and which travels further and lands softer under the finger. The column wheel was the classical construction, in the Lemania 2310-based movements of Patek Philippe and Omega, and it is the construction the in-house chronographs returned to: the Breitling B01, the Rolex 4130, the Omega 9300 and the Audemars Piguet 4401 all use one, paired with a vertical clutch.