The paper describes increased bearing capacity from 1918 to 1956 based on New Departure Laboratory endurance test results and shows an increased capacity trend up to about 1946 at which time the optimum steel cleanliness of 52100-51100 steel was obtained by an air melting practice.
The paper describes further advance in bearing capacity by the use of vacuum melting practices and also indicates that optimum cleanliness has not been consistent due to inability to control the process to the degree required for ball bearing steels.
