Although denied the attention and bravura accorded upon other inventors of his time, Johannsson worked to develop a system of precise measurement so beneficial that it completely revolutionized industrial production.
As a child, Johannsson exhibited traits that would later be important in hiswork. He kept a careful notebook in which he recorded all the events of his life, a habit he continued until his death in 1943. He also learned to work iron and steel so skillfully that his help was much sought after to repair broken tools or create new ones.
In 1882, Johannsson left his home in Götlunda, Sweden, to join his brother in St. Peter, Minnesota. The two worked in lumber camps and attended Gustavus Adolphus College until 1884 when they returned to Sweden. There, in 1887,Johannsson enrolled at the Eskilstuna Technical Sunday and Evening school and later secured a position at the Carl Gastafs Stads Rifle Factory.
Although the concept of interchangeable parts had been pioneered by Eli Whitney nearly a century earlier, in Johannsson's day there was still no industrial standard for measuring equipment, and therefore no standard machine parts to be found in any two machine shops. Each production site used its own measuring gauges--which was fine only as long as all parts were made at that plant.
Recognizing this problem, Johannsson worked to create a simple, universal measuring system . First, he studied all the parts used to make a rifle, and sketched them carefully. He realized that a relatively small number of units, each a specific length, could provide, alone or in combination, all the measurements necessary to produce these parts. This revolutionary idea was called acombination gauge block set. Johannsson's first design used 102 blocks, arranged in three series, that measured all lengths between 1 and 201 mm (0.039 and 7.84 in.) rising with an increment of 0.01 mm (0.00039 in.), making altogether 20,000 measurements obtained solely by laying two or more gauge blocks together.
Ironically, the very lack of precision machining that made the blocks necessary also made them difficult to produce. They had to be perfectly flat and parallel to provide precise measurements. To ensure accurate leveling, Johannsson invented a precision instrument that measured within 0.0001 mm (0.0000039 in.); a human hair, in comparison, is 0.05 mm (0.002 in.). After the factory had produced the blocks, Johannsson finished them at home, using a converted sewing machine to grind the blocks with a rotating wheel made of cast iron. Johannsson's blocks began selling abroad in 1901, but it was not until 1907 that they were used officially in the United States.
The gauge blocks revolutionized manufacturing, particularly the American automobile and defense industries. This change was especially apparent during World War I, when the United States was able to arm the Allies with a flood of quickly produced weapons, a feat not possible in the days of hand-finished parts and singular measuring systems. In 1923, Johannsson went to work for HenryFord at the Ford Motor Company, where he applied his gauge blocks to large-scale manufacturing. Eventually, Johannsson set up his own company which successfully manufactured standard gauge block sets and other measuring tools.