Bolt: A type of fastener consisting of a head and a screw (a cylinder with an external thread), which needs to be matched with a nut to fasten and connect two parts with through holes. So what are its main categories?

main classification

According to the force of the connection

Ordinary and with reamed holes. Ordinary main bearing axial force, can also bear less demanding lateral force. The bolts used for the reaming hole should be matched with the size of the hole and used when subjected to lateral force.

By head shape

There are hexagonal head, round head, square head, countersunk head and so on. Among them, the hexagonal head is the most commonly used. Generally, the countersunk head is used in places where the surface is required to be smooth without protrusions, because the countersunk head can be screwed into the part. Round heads can also be screwed into parts. The tightening force of the square head can be larger, but the size is large.

In addition, in order to meet the needs of locking after installation, there are holes in the head and holes in the rod. These holes can prevent the bolts from loosening when they are vibrated.

Some bolts without threads should be thin, called thin-waisted bolts. This kind of bolt is beneficial to the connection under variable force.

There are special high-strength bolts on the steel structure, the head will be larger, and the size will also change.

In addition, there are special uses: for T-slot bolts, which are most used on machine tool fixtures, with special shapes, and both sides of the head should be cut off. Anchor bolts, used for machine and ground connection and fixing, come in many shapes. U-bolts, as previously described. and many more.

There are also special studs for welding, one end has a thread and the other end is not, which can be welded to the part, and the other side can directly screw the nut.