Pan head SEMS machine screw is supplied pre-assembled with a flat washer and a spring lock washer. It features machine threads to match nuts: the flat washer distributes compressive load across the workpiece, while the spring washer provides elasticity to help resist loosening.

Materials offered are Grade 4.8 carbon steel and 304 or 316 stainless steel. Surface finishes include blue-white zinc, yellow zinc and black oxide; stainless parts are passivated. Common uses include sheet metal, electrical cabinets and general hardware assembly where a captive-washer screw simplifies fitting and reduces the risk of missing washers. Confirm required sizes, thread pitch, head drive and finish when specifying.