Proper adjustment and handling of the escapement is absolutely critical to the function of the watch. It is quite complicated and many books have been written on the topic. We will be focusing on the Swiss lever escapement made with traditional materials (steel and synthetic ruby) and covering the standards for adjustment in multiple parts.
- Endshakes and Division
- Guard Pin Shake and Horn Clearance
- Lock and Run to the Banking
Endshakes and Division
The amount of proper endshake in the escapement depends on many factors, including the total thickness of the movement and the level of manufacturing precision of the components. You should refer to the manufacturer’s specifications, if they are available. Generally speaking, the endshake in the escapement should be small but present (0.01 to 0.05mm). Typically, the endshake of the balance staff and pallet arbor are the same. The escape wheel can have a little more endshake than the pallet fork or balance staff.
All components should operate freely without rubbing or contact except where necessary. The fork slot should contact the impulse pin (roller jewel) at their center and should not be able to touch the roller table, mainplate, or shock setting in any position. The guard pin should be centered on the safety roller and safely clear the impulse pin. The escape wheel teeth should slide across the center of the pallet stones and should remain in full contact with the stones in all positions.