Abstract: A screw includes a head portion, an externally threaded shank extending from the head portion, the externally threaded shank having an external surface, and a flow-hole-forming tip disposed at a distal end portion of the externally threaded shank. The flow-hole-forming tip includes a radiused lower zone having an external surface tangent to the external surface of the externally threaded shank, a conical middle zone having an external surface tangent to the external surface of the radiused lower zone, the conical middle zone defining a vertex angle, and a radiused distal end zone having an external surface tangent to the external surface of the conical middle zone. The flow-hole-forming tip includes a width of the flow-hole-forming tip is greater than a length of the flow-hole-forming tip and/or the vertex angle is greater than or equal to 90 degrees.

Abstract: A screw includes a head portion, an externally threaded shank extending from the head portion, the externally threaded shank having an external surface, and a flow-hole-forming tip disposed at a distal end portion of the externally threaded shank. The flow-hole-forming tip includes a radiused lower zone having an external surface tangent to the external surface of the externally threaded shank, a conical middle zone having an external surface tangent to the external surface of the radiused lower zone, the conical middle zone defining a vertex angle, and a radiused distal end zone having an external surface tangent to the external surface of the conical middle zone. The flow-hole-forming tip includes a width of the flow-hole-forming tip is greater than a length of the flow-hole-forming tip and/or the vertex angle is greater than or equal to 90 degrees.

Abstract: A screw includes a head portion, an externally threaded shank extending from the head portion, the externally threaded shank having an external surface, and a flow-hole-forming tip disposed at a distal end portion of the externally threaded shank. The flow-hole-forming tip includes a convex radiused lower zone having an external surface, a concave radiused middle zone having an external surface tangent to the external surface of the convex radiused lower zone, and a radiused distal end zone having an external surface tangent to the external surface of the concave radiused middle zone.

Abstract: A thread-forming screw includes a tapered end portion formed by inserting a cylindrical blank between paired dies each having a straight portion and a tapered portion. The threads of each die are provided with undulations along their lengths corresponding to the circumference of the screw blank so as to form a trilobular thread on the screw which spirals around its circumference from one end of the screw to the other in a direction opposite to that of the threads. The cylindrical blank provides increased material at the tapered thread-forming location for forming fully crested threads, while increasing the length of the tapered portion of the die and screw provides greater stress relief for reducing the force required for thread formation and allows the screw to be driven into a workpiece more easily while maintaining a high strip force.

Abstract: A double ended stud fastening assembly with coaxially disposed stud shanks separated by an outwardly projecting rigid flange. The first shank includes a helical thread formed thereon in one direction and the second stud shank includes a helical thread formed thereon in a direction opposite the direction of the thread on the first shank. The surfaces of the rigid flange adjacent the first and second shank are substantially planar with the flange body extending perpendicular to the axis of the shanks so that when the second stud shank is mounted in a workpiece a subsequent attachment member placed over the first stud shank will be held in place by a nut.