SETTING LEVER
A setting lever is commonly associated with both the winding and time-setting mechanisms. It is a lever activated by the winding stem switches and holds the yoke in its two positions (winding and time-setting). Additionally, the setting lever secures the stem to the movement.
The setting lever emerged in 1847 with Antoine Le Coultre’s invention of the setting lever winding mechanism. Since then, it has facilitated the switching of the crown control between the winding and time-setting mechanisms, at a minimum.
The major advancements made to Le Coultre’s invention have aimed to multiply the functions adjustable by the crown. Consequently, the setting lever’s function and profile can be complex.
The watchmaker begins the artisanal production of the setting lever by engraving its profile using a tracer on the surface of a steel plate slightly thicker than the finished component. Next, the watchmaker marks the drill holes for its screw and pivot. Then, the contour of the setting lever is delicately cut using a piercing saw. The sides of the piece are then filed to bring the setting lever to its final thickness and in absolute accordance with its form. The setting lever is then beveled and polished using customary tools (files, buff sticks, polishing). According to traditional craftsmanship, the watchmaker then draws out the lines on the sides of the piece (satin finish) and the flat portion that remains on the upper surface of the setting lever.
When the setting lever is close to its final dimensions, the watchmaker adjusts the function that links the setting lever to the yoke by pre-assembling the two components to the plate. More than a dimension from a plan, this is typically an action where the watchmaker’s eye and hand remain the best tools. The stud of the setting lever can then be inserted. Heat treatments and subsequent blanching operations follow, and the setting lever is ready to be assembled.
The electrical discharge process is used to optimize production costs for a single piece or a small series of components. Implementation costs and machine processing time remain relatively low and suitable for small production volumes. Additionally, this technology allows for the cutting of complex and fine profiles without exerting any mechanical stress on the component during its fabrication. Compared to the artisanal method, electrical discharge cutting offers considerable time-saving with positive impacts on the decoration stages. The end of the manufacturing and decoration process resembles the artisanal method or the required level of finishing.
For large-scale production, the investment in a stamping tool) justifies manufacturing setting levers at an optimal cost. The expanded outline of the profile is thus stamped directly into a strip of steel slightly thicker than the finished component by a stamping press. Manual steps, however, remain unavoidable. The setting lever must be brought to its final dimensions (profile and thickness) while providing the desired finishes and decorations (satin finish, beveling, etc.).