5/16 inch Unbrako UNF Socket Head Cap Screws ASME B18.3 / ASTM A574 in Black Oxide (Self Colour) Finished Steel

Also known as an allen screw or allen bolt, or simply a cap screw. Socket head cap screws are a modern machine threaded fastener, an alternative to the standard hexagon headed bolt. The geometry of the hex drive mechanism means that these internal contact surfaces are protected from external damage. A hex or allen key is therefore required to fit these fasteners. Conforming to ASME B18.3 and material to ASTM A574, UNBRAKO® socket head caps are manufactured to be stronger than other size for size high tensile versions. Please note that due to the nature of the surface finish on Unbrako products, some surface corrosion may be evident. This does not affect the performance of the product. Minimum tensile strength of UNBRAKO® socket head caps is minimum 180,000psi which is similar to metric property class 12.9.