388 



BELL SYSTEM TECHNICAL JOURNAL 



a 



i/i 40,000 



I 

 I- 



o 



g 30,000 



q: 



I- 



<0 



to 



Z 20,000 L 



t; 40 



60 60 100 2.4 2.6 2.8 3.0 



ROCKWELL HARDNESS (E) DENSITY IN GRAMS PER CENTIMETER CUBE 



A B 



Z = TENSILE STRENGTH IN LBS./SQ. IN. 



Y=ROCKWELL HARDNESS (E) 



X = DENSITY IN GRAMS PER 

 CENTIMETER CUBE 



Fig. 14 — How control makes possible improved quality through reduction in tolerance 



limits. 



