The screw head of the hexagon socket screw is round on the outside, and the hexagon is recessed in the middle, and the hexagon screw is the type of the more common screw head with a flat hexagon.
Hexagon socket head cap screws are often used in machinery. They mainly have the advantages of easy tightening and disassembly, and not easy to slip angle. Allen wrenches are generally a 90 ° bend, one end of the bend is long and one side is short, when using the short side to screw, the long side can save a lot of force and can better tighten the screw.
The long end has a rounded head (hexagonal cylinder resembles a sphere) and a flat head. The rounded head can be easily tilted into and removed, and some parts that are not convenient for lowering the wrench are installed. The manufacturing cost of the outer hexagon is much lower than that of the inner hexagon. Its advantage is that the screw head (wrench force position) is thinner than the inner hexagon. Some places are not replaceable by the inner hexagon. In addition, the machine with low cost, low power intensity, and low precision requires less hexagon socket screws than hexagon socket screws.