For old antique watches without accessories, although the damaged hairspring can be repaired, it is difficult to reach the original running quality because the torque of the hairspring will be affected to some extent.

The trimming of hairspring is a meticulous and patient work, which can be operated on the glass plate with the help of a magnifying glass or microscope. Never make repeated adjustments to avoid adverse consequences.

When removing the hairspring from the balance wheel, put the balance wheel together with the double disc into the appropriate round hole of the anvil, pay attention to the position of the inner and outer piles of the hairspring on the balance wheel to avoid dislocation during installation, and then adjust the polarization. Then pry the bottom of the balance spring inner pile in the opposite direction at the same time with a V-shaped crowbar or two screwdrivers, so as not to affect the balance wheel. After loosening the inner pile, clamp the hairspring part on the swing shaft with tweezers.