Abstract: A screw threaded fastener (103) has an elongate shank (122) with a drilling tip (104) at one end and a head (123) at the other end. A screw thread extends along at least a part of the length of the shank (122). The trailing flank (116) of the thread subtends an angle (B) relative to the axis (117) of the fastener which approaches 90° and is greater than the angle (C) subtended by the leading flank (115). The screw is for use in fixing sheets of material a1 to thin metal battens (5) and the angle between the trailing flank (116) and the adjacent thin metal section (18) of the batten (9), being reduced in comparison to a conventional thread form, lessens the distorting effect of the thread on the batten (9) under relatively high pull-out loads.

Abstract: A fastening screw having an elongate shank (1), and a drilling tip (2) and a head (3) provided at respective opposite ends of the shank (1). The drilling tip (2) has a cutting edge (5) for cutting through metal and a flute (6) extending longitudinally of the shank (1). A thread (8) is formed on the shank (1) and extends over a portion of the section of the shank (1) in which the flute (6) is formed. A method of forming a fastening screw from a screw preform (9), includes deforming the preform (9) to create a drilling tip (2) which has at least one cutting edge (5) and a flute (6), and applying a thread (8) to the shank (1) in the region in which the flute (6) is formed.