Tightening Cannon Pinions with Plugged Ends

From Horology magazine, November, 1937

Tightening Cannon Pinions with Plugged Ends

HOROLOGY, Los Angeles, Calif.

Gentlemen:
Since many new watches have the plugged end cannon pinions it has probably occurred to many just how to tighten them. That was my worry a few months ago. Here is my solution.

Grasp the cannon pinion in a pair of cutting pliers with the pinion well over to one side of the jaws. Place a tapered broach next to the pinion, toward the inside of the jaws but not beyond the center. Give the broach as much freedom as you would were it through the center of the pinion and clamp the pliers. Try on center pinion, if not tight repeat operation. I have also found it necessary, in cleaning a watch by machine, to put a very little oil on the center pinion or the cannon pinion is apt to freeze.

GEORGE F. WISDEN 

Springfield, Ohio

Editor's Note: As the object of the broach is to provide a stop so that the cannon pinion will not be cut in two it would be a convenience to use an optician's cutting pliers, which is provided with an adjusting screw to regulate the minimum distance which the jaws can be closed.