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.
Polycarbonate is one of the toughest, most dimensionally stable thermoplastics over a wide temperature range. Impact Strength, as measured by the Izod impact test method (which measures force required to break material), is 17 pounds per foot. This is significantly tougher than standard Nylon 6/6, which is rated at 3 pounds per foot. Polycarbonate is a relatively non-hydroscopic material; it will only absorb extremely low amounts of water even after extended exposure. Polycarbonate is very resistant to greases, oils, detergents, aliphatic hydrocarbons, most mineral acids, and the higher alcohols. It is does not perform well with chlorinated hydrocarbons, and most aromatic solvents, esters, and ketones. Polycarbonate has a blue tinted transparency with 89% light transmission. Tensile strength is approximately 10,000 psi (pounds per square inch).
Generally used in electrical or radio work, these fasteners are slightly undercut under the head. That provides the ability to bind stranded wire tightly and prevent fraying. 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.