Hex bolt: A type of fastener consisting of a head and a screw (a cylinder with external threads), which needs to be matched with a nut to fasten two parts with through holes.
This connection form is called bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.
Classification
1. According to the force bearing mode of the connection, there are ordinary and hinged holes. The bolts used for hinged holes should match the size of the holes and are used when receiving lateral force.
2. According to the shape of the head, there are hexagonal head, round head, square head, countersunk head, etc. Generally, the countersunk head is used where the surface is smooth and has no protrusion after connection, because the countersunk head can be screwed into the part. Round The head can also be screwed into the part. The tightening force of the square head can be larger, but the size is large. The hex head is the most commonly used.
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 bolt from loosening when it is vibrated.
Some bolts without threads have to be thinner, called thin-waist bolts. This kind of bolts is conducive to the connection of variable force.
There are special high-strength bolts on the steel structure. The head will be bigger and the size will also change.
In addition, there are special uses: T-slot bolts, most used on machine tool fixtures, special shapes, both sides of the head should be cut off. Anchor bolts are used to connect and fix the machine and the ground. There are many shapes, U-shaped bolts , as mentioned above and so on.
There are also special studs for welding, one end has threads and the other end does not, which can be welded on parts, and the other side can be directly screwed with nuts.
