Classification and use of Hex Nut :
1. Ordinary external hexagon - widely used, characterized by relatively large tightening force, the disadvantage is that there must be enough operating space during installation, you can use an adjustable wrench or open-end wrench, or glasses wrench, and above all need a large wrench operating space.

2. Cylindrical head hexagon socket - is the most widely used of all screws, because it has a relatively large tightening force, it can be operated with a hexagon wrench, it is very convenient to install, it is almost used in various structures, the appearance is more beautiful and neat, the shortcomings The fastening force tip is lower than the outer hexagon, and the inner hexagon is easily damaged by repeated use and cannot be disassembled.

3. Pan head inner hexagon - rarely used mechanically, the mechanical properties are the same as above, mostly used in furniture, the main function is to increase the contact surface with wooden materials and increase the ornamental appearance.

4. Headless hexagon - must be used in certain structures, such as the top wire structure that requires a large jacking force, or where the cylindrical head needs to be hidden.

5. Countersunk head hexagon - mostly used in power machinery, the main function is the same as the inner hexagon 6. Nylon lock nut - inlaid with a nylon rubber ring on the hexagonal surface to prevent the thread from loosening, it is used on strong power machinery.

7. Flange nuts - mainly play a role in increasing the contact surface with the workpiece, mostly used in pipes, fasteners, some stamping parts, and casting parts.

8. Ordinary hex nut - the most widely used and one of the most common fasteners.