The FAQ of Rockwell Hardness Tester
1. Who did invent Rockwell testing method for the material testing?
Answer: It is acceptable that Mr. Hugh M. Rockwell (1890–1957) and Mr. Stanley P. Rockwell (1886–1940) from Connecticut in the United States co-invented the "Rockwell hardness tester," a differential-depth machine. They applied for a patent on July 15, 1914.[4] The requirement for this tester was to quickly determine the effects of heat treatment on steel bearing races. The application was subsequently approved on February 11, 1919, and holds U.S. Patent 1,294,171.