Socket shoulder screws provide a precision ground shoulder diameter for use as pivot pins for C-washers, swing clamp straps and other rotating components. The screw head contains socket for socket hex wrench. The threaded part of the fastener engages into the mounting surface, while the ground diameter above the thread locates the mating component. The head of the screw holds the mating component down, but does not actually pinch it in place. The mating detail is allowed to pivot around the shoulder screw. This is used in applications where one of the components makes up part of a moving assembly. The movable detail is held in its operational position by some secondary fastener, like a hand knob assembly. When specifying shoulder screws, the length of the ground shaft should always be a few thousandths of an inch longer than the thickness of the movable detail to assure freedom of movement. This is usually used to form the hinge pin to a movable detail.