Main Page | See live article | Alphabetical index A screwdriver is a device used to manipulate screws. There are many varieties, two are pictured here, the flathead and the phillips head. A typical flat head manual screwdriver. A Phillips head screwdriver. Screwdrivers come in a large variety of sizes to match those of screws, from tiny jeweller's screwdrivers up. It is important to use a screwdriver that is the right size and type for the screw used, or it is likely that the screw will be damaged in the process of inserting it. When tightening a screw with force, it is important to press the head hard into the screw, again to avoid damaging the screw. Many screwdriver designs have a handle with detachable head (the part of the screwdriver in contact with the screw), allowing a set of one handle and several heads to be used for a variety of screw sizes and types. This kind of design has allowed the development of electrically-powered screwdrivers, which as the name suggests use an electric motor to rotate the bit. Many contemporary electrical appliances, if they use screws at all, use Torx screws with oddly-shaped heads in an attempt to prevent users of the device disassembling them - see the article on screws for details. However, screwdrivers specifically designed for these special screws have become widely available in electronics stores. Screwdriver is also the name of a type of cocktail: see screwdriver cocktail This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.