The off-white nylon 6/6 machine screw has a fillister head with a Phillips drive, and meets American Society for Testing and Materials ASTM D4066 and D6779 specifications. Nylon 6/6 provides resistance to abrasion, corrosion, and many chemicals and solvents. The material is a strong yet lightweight plastic and is nonconductive. Nylon 6/6 can either absorb or lose moisture, which may alter its dimensions and mechanical properties. 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 fillister head has a slightly rounded top and tall cylindrical sides, enabling a deep drive slot for high driving force. This type of screw head is commonly used in counterbored holes. 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.
