<p>Self-drilling screw fastener (2) attaches a thin profiled or corrugated sheeting panel to a thin metallic purlin or support and includes drilling tip (18) adapted to drill a hole of a first diameter. Threaded portion (30) screws into the support and includes thread (14) with a major diameter defined by crest (14) ans a minor diameter defined by the root (22). Drilling tip (18) is sized such that the first diameter is 60% to 85% of the minor diameter and cutting faces (44) have an included anlg of 130° to 150°. Tapered portion (28) with tapered thread (15) joins drilling tip (18) to the threaded portion (30). Threaded portion (34) engages the crest of the corrugated sheet. Reamer (32) has an outside diameter less than the major diameter defined by crest (14) and is located between threaded portions (30, 34). Fastener (2) will also self-drill and fasten into timber components.</p>
