The Evolution Pancake Head Self-Drilling Metal Framing Tek 3 Screw is designed for fixing steel to steel. It has a coarse thread form (Tek 3) and is made from carbon steel with a AISI C1022 material grade, with an effective thread length of 14mm. The drilling capacity is 1.2-3.5mm and the recommended drill speed is 1500-2500 RPM.