282 ELECTRIC WELDING DEVELOPMENT. 



deal equally well witli other metals, such as copper, brass, bronzes, 

 and even lead, are characteristics of the electric welding operation. 



In its simplest form' an electric welder consists of a special trans- 

 former, the primary circuit of which receives current from an electric 

 station or dynamo generator at a voltage usually from 100 to 500 

 times that required to make a weld. The copper secondary circuit 

 of the transformer is generally only a single turn of very large sec- 

 tion, so that it may develop an extremely heavy current at from 2 

 to 4 volts — an electric pressure so low that it can not give the 

 least effect of shock, and one for which there is no difficulty in secur- 

 ing perfect insulation. The work pieces are held in clamps or vises, 

 attached to or carried upon the terminals of the single-turn secondary 

 circuit. The control of the clamping devices and the current switch 

 is either manual or, in some cases, entirely automatic. Without 

 attempting to enumerate the many applications of electric welding 

 in the arts, we may refer to a few examples. 



In the wagon and carriage industry the process is applied in the 

 production of tires of all sections, axJes, hub, spoke, and sand bands, 

 fifth Avheels, shifting rails, steps, shaft iron, etc., while it has found 

 a large use in the welding into continuous strips or bands of the wires 

 inclosed in rubber tires for holding them in place. The larger part 

 of the dash-frames used in carriages in the United States are now 

 probably made by electric welding, while iron and steel agricultural 

 wheels are built up or have their parts united by electric welds. 



To enumerate the many applications to the bicycle industry would 

 be almost to. catalogue most of the metal parts of this useful machine. 

 It must be borne in mind, too, that a welding machine, slightly modi- 

 fied, is equally applicable for locally heating parts in electric braz- 

 ing or hard soldering, for upsetting, and for bending or shaping. 

 Bicycle crank hangers, pedals, seatposts, fork and fork ends, frames, 

 and brake parts thus become products in which the welding trans- 

 former has its part. It has found a useful field also in tool manufac- 

 ture, such as drills, reamers, taps, band and circular saws, drawing 

 knives, carpenter's squares, printer's chases, etc., and electric weld- 

 ing has a closely related use in the production of machine parts. 

 Cam shafts and crank shafts are made from drop forgings welded 

 together, teeth are inserted into gear wheels, and teeth are welded to 

 saw bodies, including stone saws. Such things as inking rolls in 

 printing machines and fallers for looms are additional examples. 



In the wire industry the part played by electric welding is already 

 quite important, and becomes steadily more so. Besides the mere 

 simple joining of wires of iron, steel, or copper into long lengths, the 

 Avelding of wire or strip into hoops for barrels, tubs, pails, etc.,,is sup- 

 planting the older forms. Numerous machines are in operation turn- 

 ing out electrically welded wire fence, much as a loom turns out cloth. 



