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Carl Edvard Johansson
- Wayne State University Press
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Carl Edvard Johansson 1864-1943 "Perhaps Johansson, having nearly attained the absolute in flat surfaces, has released to mankind the initial secret of a whole new 'limb' on the 'tree of scientific growth.'" —James Sweinhart* Modern computer-programmed, numerically controlled manufacturing machines utilize Johansson gauge blocks (Jo-Blocks) for calibration. These dimensionally accurate steel blocks are descendants of the blocks invented by Carl Johansson and sponsored by Henry Ford in the days of the Model T. Carl Edvard Johansson was born on a farm at Frotuna in the parish of Gotlunda, province of Westmanland, Sweden, on March 15, 1864. He was the son of Johan and Carolina Rask Johansson. After finishing elementary school at Gotlunda Church, at age sixteen, he came to America, where his older brother, Arvid, had established himself in 1880 at Duluth, Minnesota. The brothers worked together in a lumber mill during summers, and both studied during winters at Gustavus Adolphus College at St. Peter, Minnesota. There they learned to speak English fairly well. The lumber mill burned down in 1884, and the brothers returned to Eskilstuna, Sweden, where Carl went to work at the Beronius Mechanical Works and attended Eskilstuna Sunday and Evening College. He was soon working for the Carl Gustav Stad's Rifle Factory in that city. After a two-year apprenticeship at the rifle factory, he was an accomplished machine tool engineer. In his work at this Swedish arsenal, he became acutely aware of the difficulties in making precise measurements of the sizes of parts being manufactured. Johansson conceived of a set of block gauges as a means of determining the exact dimensions of objects. The exact size would be measured by comparison with his standard blocks. When Johansson was later sent with a Swedish commission to study *From James Sweinhart , "He Measured in Millionths," Ford Times, Vol. 1,1944, pp. 18-22. 131 Henry's Lieutenants arms manufacture at the German Mauserwerke at Oberndorf, he saw similar blocks used as gauges to standardize the sizes of parts for their rifles. But these gauges were made exclusively for rifle parts. This successful use of gauge blocks convinced Johansson that a more elaborate series of blocks could be devised for universal use. After returning to the rifle factory in Eskilstuna, from 1896 to 1898, Johansson took great pains to obtain a suitable crucible steel and to develop the necessary metal finishing techniques to produce a series of blocks of exact measurements which, by various combinations, would provide any length desired by a manufacturer. By 1906, his gauges provided an accuracy approaching one thousandth of a millimeter, and in 1908 the accuracy was one ten-thousandth of a millimeter. On April 4,1896, Johansson married Fredrika Margareta (Greta) Anderson , daughter of a local brickworks foreman. She became exceedingly helpful to her husband, helping him keep records and allowing him to convert her sewing machine into a machine for finish-polishing his blocks at home on evenings after his work at the rifle factory. The Johanssons had three children—two daughters and one son. In 1911, Johansson left the rifle factory and in the same city went into the business of manufacturing his standardized steel gauge blocks for European industry. This was not an easy task, either technically or commercially. A gauge block accurately measured in Sweden expanded a bit when used in more southern countries. The dimension was only accurate when measured at the same temperature as in Sweden. Johansson fixed this temperature at twenty degrees centigrade. In some climates, certain types of steel tended to corrode and change the dimensions . A noncorrosive grade of steel was necessary. Ends of the blocks had to be perfectly flat and parallel to one another before exact dimensions could be assigned. Johansson's objectives, were, to say the least, difficult to attain, but industry was anxious to obtain a reliable standard system of measurement. Perhaps Johansson's greatest achievement was to provide gauge blocks to several government laboratories for comparison of measurements on the same blocks. Sets of blocks were measured by the National Physical Laboratory in London, and the same sets were sent to the National Bureau of Standards in Washington, the Bureau International des Poids et Mesures in Paris, and later to the PhysikalischTechnische Reichsanstalt in Berlin. Calibrations from these laboratories eventually agreed within two-millionths of an inch of one another and also within two-millionths of an inch of Johansson's originally assigned values. Elaborate optical interferometric methods were used in comparing gauge block...