Repair and Fabrication of Watch Setting Levers
In the intricate world of mechanical watches, setting levers, also known as detent springs, play a crucial role in the p
Repair and Fabrication of Watch Setting Levers
In the intricate world of mechanical watches, setting levers, also known as detent springs, play a crucial role in the precise control of the hands and the winding mechanism. Made from steel, these components are highly susceptible to breakage due to their extensive movement during operation. Here we delve into the methods for repairing or fabricating a new setting lever, focusing on the SZ1 movement as an example.
Repairing a Setting Lever Arm
– Material Selection: Choose steel of approximately 0.25-0.3mm thickness for SZ1 type levers. Old clock mainsprings of similar thickness can also serve as an alternative material.
– Shape Tracing and Cutting: Trace the shape of the broken lever arm onto the selected material, extending the break point for additional material. File the new lever arm to match the traced shape.
– Slotting and Soldering: Create a slot on the remaining part of the original lever for the extension of the new arm. Solder the new arm in place, ensuring a flat and tight joint.
– Position Adjustment: Fit the repaired lever into the movement to check accuracy, making fine adjustments as needed.
– Hardening and Polishing: The new lever arm should be hardened, tempered, and polished to ensure durability and smooth operation.
Fabricating a New Setting Lever
For levers where arm replacement is not feasible, crafting a new setting lever may be necessary. Follow these steps:
– Annealing: Begin with annealing the chosen steel or mainspring material.
– Drilling and Shaping: Drill holes for screws based on the original lever. Use these holes to secure the material and trace the lever’s outline. Cut and file the material to match the lever’s shape.
– Testing and Final Adjustments: Install the lever in the movement for testing. Make necessary adjustments to ensure correct engagement with the movement’s components.
– Hardening, Tempering, and Polishing: Complete the process by hardening, tempering, and polishing the lever for functionality and aesthetics.
Tips for Setting Lever Repair and Fabrication
– For minor wear or rust on the detent arm, local annealing and slight bending can compensate for the wear.
– Larger levers with non-top-positioned detent pins might only need the pin to be filed flat, drilled, and a new pin inserted rather than fabricating a new lever entirely.
– Early watches with screw-based levers require careful drilling and threading to ensure a secure fit.
The meticulous repair or fabrication of a setting lever is essential for the precise functionality of a mechanical watch. Through careful material selection, shaping, and adjustment, a watch can be restored to its optimal operational state, ensuring the accurate control of time-setting and winding mechanisms.
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