Carl Edvard Johansson

Carl Edvard Johansson (born March 15, 1864, Frotuna, Swed.—died Sept. 30, 1943, Eskilstuna) was a Swedish mechanical engineer. After spending part of his youth in Minnesota, he returned to Sweden and became a machine-tool engineer at a rifle factory. There he began work on the problem of precision measurement needed in the machine tools used for mass production. He devised a set of standard gauge blocks of varying size that could be put together in combinations to arrive at almost any measurement needed in a machine tool. Johansson’s blocks, known as “Jo-blocks,” were made of the highest quality steel and were fabricated to a precision that made them famous around the world. From 1925 to 1936 he worked in Dearborn, Mich., under exclusive contract to Henry Ford, who used his blocks and also sold them to other manufacturers. Johansson’s system became a fundamental component of 20th-century mass-production technique.