According to the nominal thickness, hexagon nuts can be divided into three types: type I, type II and thin. Among them, the I-type nut is divided into A-grade, B-grade and C-grade. A-grade and B-grade nuts are suitable for machines, equipment and structures with small surface roughness and high precision requirements, while C-grade nuts are used for machines, equipment or structures with rough surfaces and low precision requirements. Type II hex nuts have a thicker thickness and are usually used in applications where assembly and disassembly are often required.

The main types of hex nuts include plain hex nuts, cylindrical head hex nuts, pan head hex nuts, headless hex nuts, countersunk hex nuts, nylon lock nuts, flange nuts, etc. Ordinary hexagon nuts are versatile, but their installation requires a large operating space. The cylindrical head hexagon nut has a large fastening force and is suitable for a variety of structures, while the pan head hexagon nut is mostly used in furniture and other occasions that require appearance. Headless hexagon nuts are suitable for structures that require a hidden cylindrical head, and countersunk hex nuts are mostly used in power machinery. Nylon lock nuts prevent thread loosening by inputting nylon rubber rings in the hexagonal surface, while flange nuts improve tightening by increasing the contact surface with the workpiece.