W. G. Miller

A tool to facilitate the cutting of discs and washers out of wood, fibre, rubber and soft, thin metal, is a necessity in most electrical and mechanical workshops. The writer recently, in a short space of time and at a very slight expense, constructed the tool here described, and found it a great labor-saver in shaping mica and fiber discs for insulating the sections of a high frequency spark coil. The simplicity of construction and its adaptability to many purposes, commends it to all readers.

The rod is steel, 3 in. long; 1/2 or 1/8 in. in diameter. One-half inch from each end drill a 3-16 or 1/4 in. hole. Cut a close thread the entire length of the rod. Procure 6 hexagonal nuts which must fit the rod snugly; also some washers. Fashion from small pieces of soft tool steel the two "knife blade " cutters shown in the illustration. The holes must be the same diameter as the rod, and are not to be tapped with threads.

The cutters will be improved by hardening and tempering. From a piece of iron or steel rod make two pins, as illustrated. Drill them firmly into the end holes. The two handles are similar to awl handles, with holes drilled in the ends to fit on to the pins.

This simple tool can be set up and used in cutting discs or washers with considerable accuracy when care is taken to bind the " knife blades "securely between the nuts and washers intended to keep them in place.