The using method and working principle of screw driver
A screwdriver is a rotating screws to force the tools in place to twist, usually with a thin wedge head, the screw head can be inserted into the slot or recess -- Beijing Tianjin Hebei Jinyu and Shaanxi dialect called "screwdriver", Anhui, and Hubei, known as the "driver", the Midwest the area known as "the knife", the Yangtze River Delta region known as the "screwdriver". The main word (minus) and cross (plus two). There are also commonly used six corner screwdriver, including six corners and six corners outside two.
The screwdriver has a specialized shape of the end head aligned to the top concave of the screw, fixed, and then start rotating the handle. According to specifications, clockwise rotation is embedded; counterclockwise rotation is loose. (in a few cases, the opposite is true)
The working principle of a screw driver: when a screwdriver is used to screw a screw, it uses the working principle of the wheel and axle. When the wheel is greater the more labor-saving, so use the coarse screwdriver than using a screwdriver to tighten the screws to the fine is more labor-saving.
