Screwdriver

A screwdriver is a tool, manual or powered, used for turning screws, and is also called a turnscrew. A typical screwdriver has a handle and a shaft ending in a tip that fits into the screw head before the user turns the handle, with the shaft usually made of tough steel and the handle usually made of wood, metal or plastic, often shaped hexagonal, square or oval in cross section to improve grip and keep the tool from rolling. The earliest documented screwdrivers appeared in the late Middle Ages, probably invented in the late fifteenth century in either Germany or France, with the first documented evidence appearing in the medieval Housebook of Wolfegg Castle, a manuscript written between about 1475 and 1490; these original tools had pear shaped handles and were made for slotted screws. The Phillips screw, patented in 1932, became dominant after successful trials on 1936 Cadillac automobiles and quickly became, and remains, the most popular screw in the world. The two most common screwdriver types today are the simple flat blade for slotted screws and the Phillips driver, also called a cross recess or cross head design.