The steel thread cutting screw has a zinc plating, a Type 1 point style, and an 82-degree flat head with a Phillips drive. The screw, also called a type D thread cutting screw, has fine machine screw threads suitable for field replacement applications and a type 1 point that tapers down to a blunt edge with one flute that directs chips out of the hole to prevent clogging. Steel is often used in applications where strength is the primary consideration. The zinc plating offers corrosion resistance and has a reflective appearance. 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 Phillips drive has an x-shaped slot that accepts a Phillips driver and is designed to allow the driver to slip out of the head to help prevent over-tightening and damage to the thread or fastener.
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.