“Hoover’s greatest challenge was one of the least visible: the humble screw thread. Screws, nuts, and bolts are universal fasteners. They function in industrial societies, as one writer put it, like salt and pepper “sprinkled on practically every conceivable kind of apparatus.” Yet every such society encounters, early on, the vexing problem of incompatible screw threads. Different screws have different measurements, including the thread angles. If those don’t line up between the males and the females, you are, so to speak, screwed. .... Screw thread incompatibilities grew even more worrisome with the advent of cars and planes—complex vibrating objects whose failure could mean death. The problem had hobbled the armed forces in the First World War, which led Congress to appoint a National Screw Thread Commission. Still, it took years, until 1924, before the first national screw thread standard was finally published. It wasn’t a big-splash innovation like the Model T or the airplane, but that hard-won screw thread standard quietly accelerated the economy nonetheless.”