546 



BELL SYSTEM TECIIXIC.IL JOURNAL 



It was formerly common iirartice among many manufacturers If. 

 leave the actual planning of tlif job to the shop foreman and to sonic 

 extent this practice still exists. Obviously, under this plan, only the 

 more commonly known methods will be employed as the shop man 

 is not in a position to a\ail himself of the mass of engineering knowl- 

 edge that has accumulated in connection with such work. We are 

 convinced that the returns from engineering the actual manufacturing; 

 operations are as great as those realized from engineering the design 

 of the ])r()(iLicl. 



C\1.I.I\(. DIAL NlMlii:K 

 IM.AI'i; >* I'lMKI' 



Original I'i<()1>ii>i;i) Dksicx 



(Jl)jecli<)iial)lf features — lugs fornieil inward, ref|uires larjif blank and a cani action 



loul or two operations in forming. Small holes do not permit perforating 



Design Finally Adopted 



KfsuUs of romments^ugs formed outward decreases thi' size ol liLiiik p^■lnlil^• 



cond)incd embossing and forming in simple tool. Holes increased in >i/e 



l"ig. 2— .A Modified Part 



