Word: johansson
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Dates: during 1940-1949
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Father of all precision tools is the Johansson gauge block, invention of a Swedish genius, now made in the U.S. exclusively by Ford. With surfaces finished to an accuracy (at a constant temperature of 68° F.) within two-millionths of an inch, these blocks maintain the accuracy of micrometers and other gauges down to a ten-thousandth of an inch, thus make possible the interchangeability of parts, essence of mass production. Today, with production booming, the "Jo" blocks, always scarce, are spread as thin as management itself. Last week a lone machinist in a privy-sized Cleveland shop...
Carl Edward Johansson, working in a Swedish arsenal, cracked the accurate-measurement nut in the 1890s. He knew there was nothing so accurate in the hands of a toolmaker as a simple block of steel. Assuming that the average shop needed measurements for every ten-thousandth of an inch from 1/10 of an inch to 12 inches, a complete set of block gauges would number well over 100,000 pieces. But he found that every one of these measurements could be obtained by a combination of only 81 pieces, the smallest being 1/10 of an inch, the largest four inches...