Fig. 9
Presume the existence of a vertical line through the center of hairspring and collet as shown at "A B" Fig. 9. Then presume a horizontal line as shown at "C D" on the same cut.
Fig. 10
The proper pinning point is at the intersection of the collet and horizontal line; the spring may be either over or under even coils, depending entirely upon the location of the stud hole in the balance bridge as demonstrated by Figures 9, 10, 14, 15.
When the spring develops to the right from collet as shown in Fig. 9, for example, the proper point of attachment is on the right side of collet as shown at "E" Fig. 9, and also at "J" Fig. 14.
If it develops to the left as the springs of all fine Swiss watches do, the proper point of attachment is on the left side of collet as shown at "F" Fig. 10.
[33.]Results in Vertical Position Rates Due to Changing the Pinning Point.
In either of the above instances the spring will develop upward as it leaves the collet. These points of attachment always produce a fast pendant up rate when compared to the opposite, or pendant down rate, and all high grade watches are originally fitted with springs conforming to this principle.