The hex head cap screw is a common fastener in construction and machine assembly. The screw head is designed to fit a ratchet or spanner torque wrenches allowing you to tighten the screw to your exact specifications. Hex head cap screws are typically used to create a bolted joint, in which a threaded shaft exactly fits a corresponding tapped hole or nut. Grade 2 screws tend to be used in construction for joining wood components. Grade 5 screws are used in small engines. Grade 8 screws provide high tensile strength. One advantage cap screw fasteners have over welds or rivets is that they allow for easy disassembly for repairs and maintenance. Grainger has the hex head cap screws, nuts, washers and other fasteners you need for machine maintenance and general construction.