Hex head self-drilling screws from HANDAN DOUBLE BLUE FASTENER are engineered to be corrosion resistant and come in various sizes and materials. Depending on the size, the applications of the hex self-drilling screws can vary – the smaller screws are used in applications like fixing thin gauge metals and fixing metal to wood. The larger screws are used in roofing and other industries which require self-drilling through tough metals. Our screws come in stainless steel, alloy steel, carbon steel, and other materials that prevent corrosion. If the hex head self-drilling screws are used in extremely hard materials, it is advised to use them after a pilot hole has been drilled. Our screws are case hardened and heat-treated for applications requiring fastening of soft materials on hard ones. With a lower installation torque, the threads on these screws allow for a quick transition from drilling to tapping. For effective penetration, make sure that at least three threads of the fastener are inside the material.Roofing screws are designed specifically for all kinds of roofing applications. With a variety of types of products and good quality, our Roofing screws will provide you the best solution for fastening different kinds of roofing structures. ☆ Commonly used to fasten metal, plastic, and fiberglass roofing sheets to metal or wood structures: the roofing screws with drill points for metal structures and the ones with sharp points for wood structures. ☆ Ideal for fastening the overlap roofing sheets.