screwdriver

The screwdriver is a device specifically designed to insert and tighten, or to loosen and remove, screws. The screwdriver comprises a head or tip which engages with a screw, a mechanism to apply torque by rotating the tip, and some way to position and support the screwdriver. A typical hand screwdriver comprises an approximately cylindrical handle of a size and shape to be held by a human hand, and an axial shaft fixed to the handle, the tip of which is shaped to fit a particular type of screw. The handle and shaft allow the screwdriver to be positioned and supported and, when rotated, to apply torque. Screwdrivers are made in a variety of shapes, and the tip can be rotated manually or by an electric or other motor. China accounts for 70％ of global production of power hand tools. Exports are expected to cross the US$3 billion mark by the end of 2005, a year-on-year increase of 20％. The industry has also been expanding in terms of products made and number of suppliers. China is now home to about 2,000 power hand tool manufacturers, double the number of companies in our report of August 2004.