SHEET NON-FERROUS METALS 



795 



course, put in good mechanical condition and the methods of test 

 outHned in Appendix I were followed. The results obtained con- 

 stituted an independent verification of the conclusion that the 

 Rockwell machine was more sensitive but much less subject to varia- 

 tion and personal error than the scleroscope. 



Figure 19 is representative of the results obtained, showing a 



70 



ojoeo- 



Q. ^ 



S12 50 



HIGH BRASS 



CONSUMER 

 SUPPLIER 



4 NUMBERS HARD 



Fig. 19 — Typical Comparisons of Rockwell and Scleroscope Machines in Commercial 



Tests on Brass. 



direct comparison of the Rockwell and the scleroscope readings on 

 two tempers of high brass. It illustrates the consistency of the 

 readings of the two Rockwell instruments as compared with the two 

 scleroscopes. Figure 20 represents similar results obtained on nickel 



UJCO 



-20 

 20 



-'V-v-WwsV 



10-2 NUMBERS HARD 



6 NUMBERS HARD 



UJZ 



dS -10 



= -20 



Fig. 20 — Typical Results Showing Differences in Rockwell and Scleroscope Machines 

 in Commercial Tests on Nickel Silver. 



