With the advent of the pocketable electronic calculator in the 1970s, slide rules became obsolete for most uses. Slide rules had never been very profitable for K&E, so it was not difficult to discontinue the line. K&E's market share shrank because of other technological advancements, and the firm shut down its slide-rule engraving machines in 1975.Stoll, Cliff. "When Slide Rules Ruled." Scientific American. May 2006.
