National Electric Porcelain Co. offers new knob

National Insulator for Knob and Tube Work

This device, designed by a practical electrician with a view to convenience, is made by the National Electric Porcelain Co., of Carey, Ohio. As shown in the illustration, the projections on the bottom bite into the wood, thus preventing it from turning and letting the wire become slack.

The screw is started just enough to bring the dowel points into registration with their sockets. The wire is then placed in the gorrve, and slight twist with the pliers against the flat side of the insulator draws the wire taut. Then the screw is tightened down. The long dowel points prevent any turning of the top piece on the bottom piece. This device is also used for splicing, both grooves being used and all strain taken off the wire at the splice.