Self-Drilling Screw - Hex Washer Head Serrated - Zinc Plated Steel - 5/16"-12 Thread - 1-1/4" Long - #3 Drill Point - Pack of 700

Self-drilling screws are efficient because they eliminate the need for a pilot hole, tap their own threads, and fasten materials in a single operation. The hex washer serrated head has an external hex head with a washer-style flange attached underneath the head which creates a large surface connection area. Hex heads protrude above the surface. The externally driven head allows greater torque to be applied to the screw compared to other screws that are internally driven. The serrations provide teeth-like grooves underneath the washer that bites into the surface to resist vibration. Indentation on the surface of the head is preferred for applications involving power-driving tools. The external hex drive is designed to be used with a ratchet. Zinc plated steel offers good corrosion resistance in applications not exposed to excessive moisture.