284 ELECTRIC WEIiDING DEVELOPMENT. 



the production of automobile wheel rims, bands for roving cans, stove 

 rings, etc. 



Very different from this is the foi-niation of crank shafts, now 

 demanded in great numbers for engines of automobiles. These are 

 made from drop forgings and round shaft stock by uniting the pieces, 

 as in the annexed sketch, and afterwards lightl}^ machining and fin- 

 ishing the approximately correct shaft, as 23roduced by welding. No 

 legend. 



Besides the banding of wire or strip of such comparatively frail 

 containing vessels as barrels or pails, the electric weld finds apj^lica- 



tion in the forming and capping of 

 metal vessels for withstanding high 

 pressures, such as soda-water cylin- 

 ders, carbonic-acid reservoirs, and 

 steel bottles for nitrous oxide gas. 



One of the most interesting of the more recent applications is that 

 of welding hollow steel handles on cutlery, such as table knives and 

 forks. The operation is remarkable for the celerity and neatness of 

 the work, the articles being finished by silver-plating and polishing, 

 as usual. The hollow handle is drawn from thin steel, and united to 

 the knife blade or to the fork, as the case may be, in a special welding 

 machine, there being no brazing or other operation of joint-forming 

 required. There is, indeed, no limit to the delicacy of the work which 

 may be undertaken, provided only the welding apparatus is equally 

 refined. 



In the simpler types of electric welders, especially where the 

 machine is designed to do a variety of work, perhaps of different 

 forms or sizes of pieces, or both, the adjustments are usually manual; 

 that is to say, the operations of clamping the pieces and applying the 

 electric current and mechanical pressure are each ccmtrolled by the 

 operator. In other cases, such as in the welding of copper or alumi- 

 nium wire, the machine is, at least in part, automatic. The pressure 

 is automatically applied and the welding current is cut oft' automat- 

 ically upon the completion of the joint; the placing of the pieces in 

 the clamps and the switching on of the current is, in this case, manu- 

 ally performed. 



In other, more completely automatic, types, particularly adapted 

 for rapid repetition of the same operation on identical pieces, the 

 machine runs continuously, and its secjuence of actions is definitely 

 determined by the construction. In sucli cases a source of power, as 

 by a belt, drives the machine, the movement so imparted having the 

 effect of clamping the pieces as they are fed to the machine, j)utting 

 on the current, applying the pressure, cutting off' the current, and 

 releasing the pieces. 



The mechanism which has been developed for these purposes dis- 



