The 18-8 stainless steel thread cutting screw has a plain finish, a Type F point style, and an 82-degree flat head with a star drive. The type F point is suitable for heavy gauge sheet metal, aluminum, cast iron, brass, and plastic. The screw has machine screw threads that taper down to a blunt point with multiple cutting edges and chip cavities. The 18-8 stainless steel material provides strength and offers good corrosion resistance in many environments. The material may be slightly magnetic. The flat head has an 82-degree cone-shaped bearing surface for use in countersunk holes and a flat top that fits flush with the mated surface. The star drive, also called a Torx drive, has a six-pointed indentation that provides a large contact area for the driver, resisting slippage better than a Phillips or slotted drive. A star drive requires use of a Torx driver for installation and removal.
Thread cutting and thread rolling screws, two types of self-tapping screws, are threaded fasteners that create a mating thread in the wall of a hole. The two screws differ from each other in the way that they create the threads. Thread cutting screws cut the wall of the hole to create the thread, creating material chips that need to be cleared away from the hole to prevent clogging. Thread rolling screws, also called thread forming screws, do not remove material but instead press against the wall of the hole to displace the material and form the threads.