Fastener is a kind of widely used mechanical parts used for fastening connection. In all kinds of machinery, equipment, vehicles, ships, railways, Bridges, buildings, structures, tools, instruments, meters and supplies, all kinds of fasteners can be seen above. It is characterized by a variety of specifications, performance and use of different, and standardization, serialization, universalization of the species is also extremely high. Therefore, some people have national standards for a class of fasteners called standard fasteners, or referred to as standard parts. Fasteners are the most widely used mechanical base parts.
