A self-tapping screw is a screw that can tap its own hole as it is driven into the material. More narrowly, self-tapping is used only to describe a specific type of thread-cutting screw intended to produce a thread in relatively soft material or sheet materials, excluding wood screws. All screws require a hole. To install a screw, you'll have to insert it into the hole of a workpiece or surface. Self-tapping screws produce their own during installation. When turning a self-tapping screw with a screwdriver, it will dig into the workpiece or surface while simultaneously producing its own hole.