Self-tapping screw

For softer substrates such as wood or soft plastics, the self-tapping ability can come simply from a tip that tapers to a gimlet point (in which no flute is needed).

Like the tip of a nail or gimlet, such a point forms the hole by displacement of the surrounding material rather than any chip-forming drilling/cutting/evacuating action.

These screws combine hole drilling, threading and fastener installation into one driving motion (instead of separate drilling, tapping, and installing motions); they are thus very efficient in a variety of hard-substrate applications, from assembly lines to roofing.

[4][5] Some types incorporate a sealing washer, for fastening roofing sheets to purlins.

Self-tapping screws are used in a variety of applications ranging from DIY carpentry to surgery.

Two thread-forming self-tapping screws with different heads . The countersunk head has a Pozidriv recess.
Self-tapping screw with flute and type B (blunt) tip
A self-drilling screw and three thread-cutting screws