ARBOR

In horology and precision mechanics, the arbor is a cylindrical axis that drives other components or mechanisms in its rotation, transmitting to them movement and energy. In automatic or semi-automatic machine tools (Swiss-type lathes, milling machines), the controls are frequently provided by one or more camshafts, whose rotation paces the operations. In a watch movement, the emblematic example is the Barrel arbor: it is this that carries the Core around which the spring winds, receives the winding force from the Ratchet wheel and transmits the torque to the Barrel. The arbor differs from the axis by its active driving function: it does not merely guide a rotation, it transmits it. The precision of its bearing surfaces and pivots determines the efficiency and longevity of the assembly. As a structuring element of any kinematic chain, the arbor is at the heart of energy transmission, both in the watch and in the machines that manufacture it.