Abstract
Although a large number of studies have been made on screw threads, little is known about mechanical screw. The aim of this paper is to improve the reliability of bolted screw joint design by clarifying the relationship between hardness and tensile strength and strength use efficiency of cross recessed pan head mechanical screw. In conclusion, (1) Real tensile strength of mechanical screw products is lower than the value estimated by relational expression, (2) Tightening axial force has a constant limiting value, (3) Strength use efficiency decreases as the nominal diameter becomes bigger.
