Development and Manufacture of Electroformed Conductor for Telephone Drop Wire

Telephone drop wire is that familiar black overhead wire which brings the telephone service to the home. It is a parallel pair of conductors separated and positioned in an extruded insulation, covered by a cotton serving and jacketed with a neoprene compound of tire tread-like qualities. In the past, a cast copper jacketed steel ingot, rolled and drawn to size, has been used to provide a wire that combines high strength and good conductivity. In order to assw-e more than a single source of supply and to provide improved mechanical and electrical characteristics, a completely new plant has been constructed for continuous plating of steel wire at completed size. This process provides a stronger, yet smaller and, therefore, less costly wire than was possible previously. Plating is done at 100 feet per minute on 25 wires simultaneously. The conductor is then processed as formerly to provide the neoprene jacketed drop wire. HISTORICAL BACKGROUND It has been customary in manufacture to apply a lead and a brass plate to drop wire conductor to secure good adhesion to the insulating compound. The brass provides the adhesion while the lead prevents attack on the copper by the sulfur in the rubber. In 1941, two tandem lead and brass plating machines were placed in service at the Point Breeze Works of the Western Electric Company to apply these coatings on a production basis. Their successful operation proved that electrolytic deposition of two metallic coatings in tandem at high speed was commercially practicable.