Great care must be taken when removing the balance staff from the beryllium alloy balance wheel. The material is much softer than steel and is easily distorted when the staff is removed, and once distorted it is difficult to restore it to its original state.

This is Cal.1520 of Rolex Submariner, Ref.5513.

How to make a balance staff is the same as usual.
Please refer to the link below.

Making balance staff

Left : What I made.
Right : The broken one.

Completed!