Historians believe that the first screw thread was probably made about 400 BC, and hole-making devices go back much further. Despite the age of these basic processes, significant improvements are continually made. Most of the upgrades have been driven by the needs of the aircraft, medical, and petroleum industries, where the leading requirements are precision, productivity, small size, and in many cases, cleanliness. When making holes 2" (50 mm) and smaller, the drill is still the dominant tool, with lasers, waterjet, and E.D.M picking up up a growing number of jobs.
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