Will you kindly publish an article on pinning a hairspring to the stud or collet in your next issue of Horology?
Next insert the inner end of the spring in the hole of the collet and with a tweezer put in a hairspring pin as far as it will go. Pins used for regulators are . best for they have a more gradual taper and will hold better. Now check the spring to see if it is level before fastening the pin permanently.
If satisfied with its appearance grasp the small end of the pin with a fine flat pliers and pull it until it is forced tightly in the hole. Then by giving the pin one or two sharp twists with the plier break it off. If done right the pin will break off cleanly at the edge of the hole in the collet. The large end is then broken off in the same manner. So much for the collet.
The tool shown in Fig. 2 is very convenient for holding collets while pinning springs. A broach is held in the center of a white disc by means of a set-screw.
The handle is hollow and contains a compartment for extra broaches of various sizes. It is manufactured by L. F. Acker, Springfield, Ill.