The Hillman GroupThe Hillman Group 35259 Hex Washer Head Self-Piercing Screw 8 x 3/4 75-Pack They are used in wood, fiberglass and metal Self-drilling or self-tapping metal screws increase productivity by reducing the number of steps required to screw together pieces of metal Zinc-Plated The self-drilling screw possesses a drill point enabling it to drill in its own hole in thin gauge steel