Like the English Hardometer - made byThos Firth & John Brown Ltd of Sheffield - and similar machines from other makers -  Pittsburg hardness tester used the Brinell method where a ball of hard steel was pressed, by a known force, into a test sample. However, instead of a falling or spring-controlled weight being used, one version of Pittsburg was motor driven and used an adjustable hydraulic cylinder to develop the necessary force. By this means it was possible to greatly increase the work rate; however, for shops where only occasional testing was required, a cheaper hand-operated type was available..