Abstract: An engagement structure for a tool contains: a drive member which includes an accommodation orifice, a hexagonal tooth portion, and six planes. A respective one of the six planes is arranged on a center of a respective one of six peripheral sides of the hexagonal tooth portion, and the two beveled rims extends from the two sides of the respective one plane and are connected with a first adjacent beveled rim of a first adjacent plane and a second adjacent beveled rim of a second adjacent plane. A ratio of lengths of the respective one plane, the first adjacent beveled rim and the second adjacent beveled rim is 2:1:2, and an angle between the respective one plane and each of the first adjacent beveled rims and the second adjacent beveled rim is 2 degrees.

Abstract: An engagement structure for a tool contains: a drive member. The drive member includes an accommodation orifice defined in the drive member, a hexagonal tooth portion formed around the accommodation orifice, and six arcuately concave sections respectively arranged on six sides of the hexagonal tooth portion. Each of the six arcuately concave sections is arranged on a center of each of the six sides of the hexagonal tooth portion. The drive member further includes multiple bevel rims, any two spaced of the multiple bevel rims respectively extend from two sides of each arcuately concave sections, and any adjacent of the multiple bevel rims connect, wherein an inclined angle each of the multiple bevel rims is 2 degrees.