It should be noted that although external hexagonal bolts have various advantages, they also have limitations in certain situations. For example, they cannot be used on thin-walled parts or in situations where they are subjected to impact, vibration, or alternating loads. If they exceed a certain length, they do not have full threads, tightening tools are not easy to match, and they are easy to screw and replace. A professional wrench should be used for disassembly, which is not easy to disassemble normally.