ISO 4753 is the fundamental international standard that specifies the types and dimensions of ends for fasteners with external metric ISO threads. It defines the geometry of bolt and screw tips to ensure proper lead-in during assembly and to protect the first few threads from deformation.

This standard is essential for high-speed automated assembly lines where precise end shapes, such as chamfered, rounded, or dog points, are required to prevent cross-threading. It covers all common fastener products including bolts, screws, and studs, establishing a universal language for engineering end-geometry.

The technical focus of ISO 4753 is Lead-in Efficiency. By standardizing the angle of chamfers ($45°$) and the radius of rounded ends, the standard guarantees that the bolt will find the center of the tapped hole or nut effortlessly. Specialized ends like the "Pointed End" or "Long Dog Point" are specifically engineered for locating holes in multi-layered components or providing a pivot point in mechanical linkages.