ELECTRIC WELDING DEVELOPMENT. 285 



plays, in many instances, nuich ino-enuity. In tliose niachiiics the 

 fluty of the attendant is limited to the niei'e j)hicing of the pieces 

 between the chimpinfj jaws, just before they are chimjjed, and the 

 work is characterized by rapidity and by uniformity of the results. 



More completely automatic still are machines for the production 

 of wire fencings and for the consecutive welding of the links of 

 chains. In these the operation, once started, goes on uninterruptedly 

 so long as the work holds out or until the stock undergoing opera- 

 tion is exhausted. In the fence machines, of which 15 are now in 

 existence, galvanized iron Avires are fed from reels parallel to one 

 another, at distances a})art depending on the mesh desired. These 

 may correspond to the warp in weaving. Transversely to these and 

 at intervals corresponding to the mesh selected are fed wires, cut 

 from a reel, which transverse Avires are the verticals in the finished 

 fence itself and correspond to the weft in weaving. A series of 

 small welders are autonuitically brought into operation to weld each 

 transverse wire to the longitudinals where the two cross. This done, 

 the web so formed moves forward, the operation repeats itself, and 

 so on continuously. The Avelding is in this case practically instan- 

 taneous, and all of the movements of the machine are entirely 

 automatic. 



In this way it is jjossible for a single machine to turn out many 

 thousands of feet of fencing per day with a width of mesh from 2 

 or 3 inches up. Less wire is used than where the joints are made by 

 tAvists or loops, and the stability or fixedness of position of such 

 joints as are made is much more assured. Figure 1, plate in, will 

 give some idea of the neatness of this jjroduct of the electric welding 

 loom. 



While in most cases of electric welding the joint forms what is 

 jcnown as a butt weld, with a burr or extension of metal at the joint, 

 Avhich, according to conditions, is either allowed to remain or is 

 forged down or di-essed off', there is no difficulty in making la]) Avelds 

 electrically, and some of the I'ecent work of the electric welder is of 

 that character. While, too, the usual welding concerns pieces of 

 the same metal, as iron to iron, steel to steel, or coi)|)er to copper, 

 combination welds of different metals are made Avith facility in many 

 cases, as Avhen brass and iron are united. 



In the Avorking of high-carbon steels the usual ju'ecautions to 

 prevent burning or injury to the metal are, of course, refpiired ; but, 

 on account of the delicacy of heat control, they are more easih'^ 

 adopted. 



Quite recently automatic chain AV(^lders have been ])ut into use, and 

 electrically-Avelded chain work will probably soon attain an impor- 

 tance not second to the other principal applications which have been 

 brieflv described. 



