Self-tapping screws are ideal for a variety of materials
Self-tapping screws can be divided into two categories; thread-forming self-tapping screws and thread-cutting self-tapping screws.
Those screws that displace material (especially plastic and thin sheet metal) without removing it are called thread-forming self-tapping screws; Self-tapping screws with a sharp cutting surface that removes material upon insertion are called thread-cutting self-tapping screws.
Self-tapping screws are designed to cut their own holes as they are screwed into the material.Self-tapping screws are ideal for a variety of materials, including wood, plastic, metal and brick. For harder surfaces, self-tapping screws may have small notches in the threads to help cut the threads. These threads are called serrated threads.
Self-tapping screws come in many tip types and thread patterns. Not all self-tapping screws have a pointed head; some will have a blunt or flat head. So the three basic types of self-tapping screws are self-tapping, self-drilling and self-piercing. But all Self-tapping screws are fully threaded, with threads covering the entire length from tip to head, and are surface hardened.