The Bell System Technical Journal 



July, 1928 



Precision Tool Making for the Manufacture of 

 Telephone Apparatus 



By J. H. KASLEY and F. P. HUTCHISON 



THERE is probably no field of human endeavor in which hand 

 labor has been more completely replaced by labor-saving devices 

 than in the field of manufacturing. The design and employment of 

 special tools together with semi- and full automatic machinery for 



ERRATA: Bell System Technical Journal, April, 1928 



Page 327, Table 2 — Interchange the number "200" of column 6 and 

 number "600" in column 8. 



Page 328, beginning line 4, should read — (a) Phantom to phantom; 

 1 represents the two wires, connected in parallel, of one pair 

 of a quad. 2 represents the two wires in parallel of the other 

 pair of the quad, and 3 and 4 represent similarly the pairs of 

 another quad. 



Page 347 — Figure 3 should be inverted. 



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tool maKmg arc as pictuLiL,c(a uy um^ •._wiixptiii_x cvxxv^ ^^ ^^ ^.— ^, 



tive material will be drawn from among the large number of punches 

 and dies used for punch press methods of manufacture. The methods 

 employed and precision necessary in building the tools discussed below 

 can be considered as representative of the high class of workmanship 

 required throughout the Company's tool rooms. 



Punches and Dies 



Tool Making for Telephone Apparatus Manufacture. Briefly, a 

 punch and die comprises a pair of individual tools so constructed 

 25 375 



