Stanley P. Rockwell invented the Rockwell hardness test. As a metallurgist for a large ball bearing company, he wanted a fast, nondestructive way to determine if the heat treatment process they were doing on the bearing races was successful. The only hardness tests he had available at the time were Vickers, Brinell and Scleroscope. The Vickers test was time consuming, Brinell indents were too big for his parts and the Scleroscope was difficult to use, especially on his small parts.
To satisfy his needs, he invented the Rockwell test method. This simple sequence of test force application proved to be a major advancement in the world of hardness testing. It enabled the user to perform an accurate hardness test on a variety of part sizes in just a few seconds.