Machine Screws, also referred to as Machine Bolts, are often used with nuts or driven into tapped holes. They come in a variety of head types and drive styles, but are generally available in smaller sizes.
Acetal resins are characterized by their strength, stiffness, and hardness, and are stable over a wide range of temperatures, humidity, environments, and stress. Acetal has a low coefficient of friction, and absorbs little water, minimizing the effect of moisture on its physical properties. Acetal resists neutral oils, grease, petroleum-based fuels, many organic solvents, alkalis, oxidizing agents and acids, both organic and inorganic. Compared to Nylon 6/6, Acetal is harder and has better water resistance, but lower impact strength and abrasion resistance. Acetal is translucent off white in color.
Pan head fasteners have a low, large cylindrical head with a high rounded top edge for higher tightening torques - these fasteners are often recommended to replace older head styles such as round, binding, or truss-head where possible. Common applications for slotted screws include woodworking, although the drive style is not designed to be used with power drivers.
A threaded fastener's size name includes information about the major external diameter, followed by the threads per inch, which indicates if it is coarse or fine.