Dottie Self-drilling Phillips wafer-head screw measuring 1-1/4-Inch x size 8, helps to drill hole and tap threads in one operation. This self piercing/self-tapping screw in zinc-plated finish, features steel construction. Screw taps its own mating threads when driven into preformed holes in metal. Drilling operation in this screw removes metal and is suitable to use with heavier gauge metals.