Indicated by "N" (Near side) or "F" (Far side) to show where the manufactured head should rest. AIA/NAS - NAS523 - FASTENER CODE | GlobalSpec
Required hole preparation (e.g., dimpling or countersinking). SE (Southeast): Fastener length. Breakdown of the NAS523 Symbol Quadrants
This quadrant specifies the fastener's basic part number (often or MS standards) and the material it is made from. nas523 pdf
Often identifies an MS20426AD rivet (countersunk 2117 alloy). ↗️ Northeast (NE): Diameter & Head Placement
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? Indicated by "N" (Near side) or "F" (Far
The system uses a symbolic "cross" located on blueprints to give technicians immediate instructions for a specific location: Part number and material alloy code.
Fastener diameter and manufacturer head location. Breakdown of the NAS523 Symbol Quadrants This quadrant
Understanding the "crosshair" is critical for any aviation maintenance engineer (AME) or technician working with sheet metal. ↖️ Northwest (NW): Identity & Material
This quadrant indicates the shank diameter, typically in increments of .