PROBLEMS IN DIMENSIONS AND TOLERANCES 



187 



by this type of experiment using a sufficiently large and representative 

 sample would be practicable and would permit considerable condensation 



I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 



NUMBER OF UNITS IN ASSEMBLY (ALL ONE KIND) 



Fig. 3 — Statistical relationship of overall tolerance on an assembly and the sum of the 

 individual part tolerances 



28 29 30 31 32 33 34 35 



THICKNESS AT CENTER OF CELL IN THOUSANDTHS OF AN INCH 



Fig. 4— Distribution of thickness in 2083 pileup insulators 



of design on a sound basis. In this particular case the parts used apparently 

 came from only two different sheets of fiber as indicated by the distribution 

 of thickness of the individual parts shown by Fig. 4. 



