Screw Thread and Countersunk Head Diagram - Engineering Illustration #3101516 (License: Personal Use)

This black-and-white engineering schematic depicts a countersunk-head screw inserted into a workpiece, with diagonal hatching indicating the surrounding material. The helical threads are shown in profile, including both solid and dashed lines to represent visible and hidden geometry. The recessed head fits flush with the surface, demonstrating proper installation for load distribution and clearance.

Used in mechanical engineering textbooks, CAD documentation, fastener specification sheets, and DIY hardware guides; targets users seeking to understand screw geometry, installation depth, or stress distribution in joined materials.