A self-tapping screw is a screw that can tap its own hole as it is driven into the material. Some self-tapping screws are also self-drilling, which means that, in addition to the tap-like flute in the leading threads, there is also a preliminary drill-like fluted tip that looks much like the tip of a center drill.
Has sharp threads that cut into a material such as sheet metal, plastic or wood. They are sometimes notched at the tip to aid in chip removal during thread cutting. The shank is usually threaded up to the head. Sheet metal screws make excellent fasteners for attaching metal hardware to wood because the fully threaded shank provides good retention in wood.