Plug-in Type Electric Power Control.
There's a decided advantage in being able to suit the speed of your drill or saber saw to the job at hand. This control box is a compact, inexpensive unit you can make yourself. It plugs in directly to any wall outlet, which means that when you're not using it in the shop you can take it anywhere in the house to serve as a light dimmer, a temperature control for an electric heater - or as a speed control for kitchen appliances.
Rated at 600 watts of control power and has a smooth continuous range from 'on' to 'off'.
Three pages ( 2 sheets - front on first sheet, front and back on second sheet ) B & W photos, illustrations, expanded view, parts list and instructional narrative.
My plans are from original source materials such as books, magazines and other publications and the pages are carefully removed.