Understanding the "crosshair" is critical for any aviation maintenance engineer (AME) or technician working with sheet metal. ↖️ Northwest (NW): Identity & Material
Often identifies an MS20426AD rivet (countersunk 2117 alloy). ↗️ Northeast (NE): Diameter & Head Placement nas523 pdf
The (National Aerospace Standard 523) is a vital fastener coding system used throughout the aviation industry to standardize the identification and installation of permanent fasteners, particularly solid rivets. This system simplifies complex engineering drawings by consolidating critical data—such as part numbers, diameters, material alloys, and hole preparation methods—into a single four-quadrant "crosshair" symbol. What is the NAS523 Fastener Code? Understanding the "crosshair" is critical for any aviation
This quadrant indicates the shank diameter, typically in increments of . nas523 pdf
Fastener diameter and manufacturer head location.