What are the classifications of Hex Bolts?

Update:07-09-2018
Summary:

1. According to the way of connection, there are common […]

1. According to the way of connection, there are common and reamed holes. The bolts for reaming holes should match the size of the holes and be used when subjected to lateral forces.
2, according to the shape of the head has a hexagonal head, round head, square head, countersunk head, etc. The general countersunk head is used in places where the surface is required to be smooth and not protruding, because the countersunk head can be screwed into the part. The head can also be screwed into the part. The tightening force of the square head can be larger, but the size is large. Hex heads are 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 rods, which can not loosen the bolt when it is vibrated.
Some bolts with unthreaded rods are to be thin, called thin waist bolts. These bolts are beneficial for the coupling of variable forces.
There are special high-strength bolts on the steel structure. The head will be larger and the size will change.
In addition, there are special uses: T-slot bolts, the most used on machine tool fixtures, special shape, cut off both sides of the head. The anchor bolts are used for fixing the machine and the ground. There are many shapes, U-bolts , as mentioned above and so on.
There is also a special stud for welding. One end has a thread and one end is not welded. It can be welded to the part and the other side can be directly screwed.