Hexagon socket bolts can withstand large moments. The disadvantage is that the tangential force is almost parallel to the hexagonal surface, and the hexagonal surface is easy to be ground. In order to solve this problem, the star bolt was invented, so that the tangential force of the rotating torque is almost perpendicular In the star-shaped plane, the life of bolts has been greatly improved, but the disadvantage is that the manufacturing costs of bolts and tools are higher than those of hexagon sockets...
Two types of screws/bolts are mostly used in machinery and equipment. Star screws are commonly found in imported brand equipment, such as the most imported electric tools I have seen. In addition to being more susceptible to stress, the two also have advantages in terms of wear and tear, and are also used as special parts to prevent non-professionals from disassembling restrictions.
Hexagon socket screws are now very common, and they are often seen when assembling furniture. The manufacturing cost is lower than that of star screws, and the tools are easy to obtain. The disadvantage is that it is easy to damage when the diameter is less than 3mm. The reason is that as Gengjin Fasteners said, I have a bunch of wrenches that are shaped into round bars; the star screws make up for the shortcomings of the hexagon socket screws to a certain extent, especially in When the screw head diameter is small. However, the manufacturing cost and accuracy are somewhat difficult. The contact depth of the screwdriver is small, which is not common in narrow areas. Therefore, I have never seen an L-wrench and a star screw with a large screw head.
