TOTAL LOCK

This is the angle corresponding to the travel of the escape wheel across the locking face of the pallet and the run to the banking. Proper adjustment of the total lock on both pallets of the lever during escapement adjusting is essential to ensure the good functioning of the watch. Its value is considered correct when it lies between 1/4 and 1/5 of the length of the pallet impulse plane. This value is adjusted by moving the pallet jewel deeper into or further out of the lever fork using an escapement tester.

Useful link:
– Escapement adjusting