The straightening of a hairspring is a difficult and tedious job. First unpin the spring from its stud and place it on a watch glass upon a sheet of white paper. Then with two pairs of fine-pointed tweezers, one pair in each hand, proceed to re-shape the faulty coils. Begin at the centre of the spring, and follow it round with the eye until the exact point of the first departure from trueness can be noted. Rectify this and proceed, always working from the centre to the outer coils. First get the coils concentric, true, and at equal distances from each other. Then proceed to get the spring flat, working as before from the centre to the outside. To act properly a hairspring must be flat, true in the "eye," and all the coils must be free of each other and at an equal distance. The outer coil should pass freely between the curb pins and, when the balance is at rest, should not touch either curb pin.