The steel machine screw has a zinc plated finish and a pan head with a Phillips drive. Steel is often used in applications where strength is the primary consideration. The zinc plating offers corrosion resistance and a reflective appearance. 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. The pan head has a flat top and short vertical sides with a rounded top edge.
Machine screws are threaded fasteners that are typically used with nuts or drilled and tapped (threaded) holes. Machine screws are available with a variety of head shapes, which determine how the screw interacts with the mating surface, and drive styles, which determine the type of driver required to install and remove the screw.