: Reverse reads, "Credit, Allen Bishop. Columbus, Ohio. Thickness gauge."
An unidentified man uses a Rockwell scale that tests the indentation hardness of a material in Columbus, Ohio. This tester was patented in 1914 and is used mostly in engineering and metallurgy industries. More information needed. View on Ohio Memory.
: SA1039AV_B07F10_021_1 Subjects
: Industries--Ohio--History--Pictorial works; Factories--History;Pipe industry--United States; United States. Work Projects Administration (Ohio) Places
: Columbus (Ohio); Franklin County (Ohio)