To provide a stud to be engaged with a female threaded portion of a blind hole and a bolt engaged with a female threaded part in a through-hole and fitted with a nut, eliminating a slack in the stud or the bolt even if the arrangement is such that the through-hole does not accept thread cutting or the bolt end does not accept nut setting.

A working hole 2 is formed at the end of the stud 1, a cut-in groove 3 is formed at the periphery of the hole, and an elliptical sphere 4 slightly greater than the diameter of the working hole 2 is provided and then bonded to the end of the working ball 4 in such an arrangement that the longer axis of the elliptical sphere 4 and the axis of the working hole 2 are aligned, whereby the end of the male threaded portion of the stud or the bolt is rolled up.