Self drilling coarse thread screws are used for fixing into metal such as in carport, shed, garage and steel frame construction. The hardened steel self drilling point (often going by its proprietary name tek point) can self drill through varying gauges of mild steel without the need for pre-drilling (see product attributes for material thickness constraints), accompanied by 18 TPI (thread per inch) coarse thread for rapid install into the steel. with its countersunk head, self drilling (tek) point and coarse thread, this screw is ideal for steel construction where a discrete finish is required.