1, according to the connection of the force, there are ordinary and hinged hole with the hinge hole with the hole to match the size of the hole used in the horizontal force.
 
2, according to the shape of the head has a hexagonal head, round head, square head, countersunk head, and so the general Shen head used in the request after the connection surface is not smooth place, because the countersunk head can be screwed into the parts. The head can also be screwed into the part. The square head of the tightening force can be larger, but the size is very large. Hex head is the most commonly used.
 
In addition, in order to meet the needs of the lock after installation, there are holes with holes, the stem of the hole, these holes can make the bolt when the vibration is not loose.
 
Some bolts do not thread the light rod to do fine, called thin waist bolts. This bolt is conducive to the connection by the force.
 
There are special high strength bolts on the steel structure, and the head will be bigger.
 
In addition there are special use: T-shaped slot bolts, the machine fixture used on the most special shape, both sides of the head to be cut off the anchor bolts for the machine and the ground connection fixed, there are many shapes, U-shaped bolt , As mentioned above and so on.