Socket for turning nut, has withholding part including grooves and projections that have enlarged parts, where ratio of widths between enlarged parts and widths in bottoms of grooves is of specific value

摘要

The socket has a connection cavity (53) and a withholding part (51) defined in respective ends of a tubular body (50). The withholding part includes projections (55) and grooves (54) arranged sequentially in an inner periphery of the withholding part. Each projection has an enlarged part, where the ratio of widths between the enlarged parts and the widths in the bottoms of the grooves is 1:1.2.