Types of standard parts

1.Bolt: it is a kind of fastener, which is composed of head and screw(cylinder with external threads), it needs to be matched with a nut for connecting two parts with through holes. This type of connection is called bolt connection. If the nut is screwed down from the bolt, the two parts can be separated so that the bolt connection is called detachable connection.

2.Stud: it is a kind of fastener, which has no head and has outer thread at both ends. When connected, it’s one end must be screwed into a part with inner screw holes, and the other end need to pass through the parts with through holes, and then the nut is screwed, and the two parts are connected to form a whole. This type of connection is known as stud connection, which is also called a detachable connection, it is used for connecting parts with a larger thickness and compact structure, or it is used in the occasions that due to frequent demolition, it is not suitable for the use of bolt connection.

3.Screw: it is also a kind of fastener, which is composed of head and screw arbor, it can be divided into three categories according to its application: machine screws, set screws and special purpose screws. The machine screw is mainly used for fastening a screw thread hole part, which is connected by a part with a through hole, it doesn’t need to match the nut(this connection is called screw connection, also belongs to the detachable connection, also can be matched with a nut used for the fastener connection between the parts with a through hole.) The fastening screw is mainly used to fix the relative position between the two parts. Special purpose screws such as screw ring are used for hoisting parts.

4. Nuts: it has an internal thread hole, the shape is flat six prism, flat square cylindrical or flat cylindrical, it is matched with the bolts, studs or machine screws, which is used for fastening connecting two parts to make it become a whole.