A machine screw is a fastening screw with a machine-cut thread throughout the length of its shank, for use with a nut or driven into a tapped hole. Use to fasten various components together in machines, tools, etc. The length of a machine screw is measured from under the head to the point of the screw. The truss head has a low rounded top surface with a flat bearing surface, greater in area than a round head fastener of the same nominal size. They are weaker than a pan or round fastener, but preferred in applications where minimal clearance exists above the head. The profile provides a trim, finished appearance.
Machine screws are used with nuts or screwed directly into a threaded receptacle to fasten metal parts together. Measured from the underside of the head to the tip of the screw to obtain fastener length. If nuts are needed, use with nuts of the same finish and threading for proper fit.