self-tapping screw

A self-tapping screw is a type of screw that can form its own threads in materials like metal, plastic, or wood when it is screwed into a pre-drilled hole. These screws create mating threads by either displacing the material around the hole, allowing it to flow around the screw, or by cutting the material, similar to a tap, to remove it and form the thread. This capability makes them useful for fastening machine parts together without the need for a pre-tapped hole.1

The concept of the screw itself dates back to ancient times, with evidence of its use in devices like water screws and presses dating back to ancient Greece and Egypt. Modern screws, including machine screws and cap screws, are used to clamp parts together by stretching when tightened, creating a clamping force.1