UNC Socket Head Cap Screws ASME B18.3-2012 in Bright Zinc Plated (BZP) Steel
Also known as an Allen screw or Allen bolt, or simply a cap screw, socket head cap screws are a more
modern alternative standard machine fastener to the standard hexagon headed bolt or setscrew, as found
on much modern machinery. A hex key (otherwise known as an Allen key) is required to fit these fasteners.
Conforming to ASME/ANSI B18.3, the contact surfaces of this screw or bolt are protected from external
damage. Generally manufactured with a partial thread beyond a certain length and nominal diameter combination,
but occasionally some stock may include a fully threaded shank at the same combination.
