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Similar to sheet metal screws, but they have a drill-shaped point to cut through sheet metal or steel which eliminates the need for drilling a pilot hole. These self-drilling screws are designed for use in soft steel or other metals.Self-drilling screw points are numbered from 1 through 5, the larger the number, the thicker metal it can go through without a pilot hole. A 5 point can drill a 0.5 in (13 mm) of steel, for example.Self Drilling Screws are used primarily when fastening into steel or other metals and are typically used to join materials like sheet metal. These screws are identified by the unique point or flute at the end of each screw.

The ability of a screw to advance when turned, while creating its own thread versus, say, machine screws which require a pre-threaded nut or other female insert. Self-Tapping screws can cut their own threads as the screw is driven in to the material. They function by having a cutting edge which drills away the material, making a tiny hole for the screw to go into. This has nothing to do with the point of the screw but has everything to do with the threads which are designed to cut through the material.Self-tapping screws have a wide range of tip and thread patterns, and are available with almost any possible screw head design. Common features are the screw thread covering the whole length of the screw from tip to head and a pronounced thread hard enough for the intended substrate, often case-hardened.For hard substrates such as metal or hard plastics, the self-tapping ability is often created by cutting a gap in the continuity of the thread on the screw, generating a flute and cutting edge similar to those on a tap. Thus, whereas a regular machine screw cannot tap its own hole in a metal substrate, a self-tapping one can (within reasonable limits of substrate hardness and depth).