National Geographic : 1947 Apr
Man's Mightiest Ally Interchangeable Parts Teach the Young Engineer to Build His Own Steel Empire An electric motor powers this miniature crane, made from an Erector set's stamped-steel beams, girders, and plates. During the war the famed Bailey bridge was developed with the aid of two Erector kits flown to England. O National Geographic Society KIodachlromes Iby illard 1. Culver For Lack of the Lowly Nail, America Faced a Crisis Factories even bent old nails and re-used them. A veteran said: "I have all it takes to build a home but a keg of nails." Once made by hand, nails now are turned out by machines faster than the eye can follow.