Double-ended stud with combined driving and locking means

A fastener member including a first stud shank with a flange extending radially therefrom, said first stud shank including a helical thread formed thereon, said helical thread incorporating means to form a mating internal thread in a preformed bore in an associated work surface, the flange defining a lower surface adjacent said first stud and an upper surface opposite to said lower surface, upstanding protuberance means formed on said upper surface of the flange, said protuberance means including generally radially extending ribs each having a primary rotary driving surface extending upwardly perpendicularly from the upper surface of the flange, an upper surface on said protuberance formed as a first planar surface intersecting the primary rotary driving surface and extending generally perpendicular thereto, a secondary surface defined by a second planar surface which extends upwardly at an acute angle from the plane of the flange, the line of intersection between said first and second planar surfaces lying in a plane which extends generally tangentially from said first stud shank toward the primary driving surface, said line of intersection thus being disposed at an acute angle to the line of intersection between the first planar surface and the primary driving surface, said protuberance means being adapted for one-way engagement by a mating tool to rotate the fastener member about its axis into the bore in the associated workpiece.