The NAS523 (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?
The NAS523 code is a standardized practice that includes all types of fasteners that undergo permanent deformation during installation. Removing these fasteners typically requires their destruction, making precise initial installation essential for structural integrity.
The system uses a symbolic "cross" located on blueprints to give technicians immediate instructions for a specific location: NW (Northwest): Part number and material alloy code.
NE (Northeast): Fastener diameter and manufacturer head location.
SW (Southwest): Required hole preparation (e.g., dimpling or countersinking). SE (Southeast): Fastener length. Breakdown of the NAS523 Symbol Quadrants
Understanding the "crosshair" is critical for any aviation maintenance engineer (AME) or technician working with sheet metal. ↖️ Northwest (NW): Identity & Material nas523 pdf
This quadrant specifies the fastener's basic part number (often AN or MS standards) and the material it is made from.
BJ Code: Often identifies an MS20470AD rivet (2117 aluminum alloy).
BB Code: Often identifies an MS20426AD rivet (countersunk 2117 alloy). ↗️ Northeast (NE): Diameter & Head Placement
This quadrant indicates the shank diameter, typically in increments of 1/32 of an inch.
Manufacturer Head Location: Indicated by "N" (Near side) or "F" (Far side) to show where the manufactured head should rest. AIA/NAS - NAS523 - FASTENER CODE | GlobalSpec The NAS523 (National Aerospace Standard 523) is a
The NAS523 standard, often called the "Rivet Code," establishes a four-quadrant symbolic system on engineering drawings to specify fastener part numbers, material, diameter, and installation methods in the aerospace industry. This standardized system allows for precise identification of rivet requirements, ranging from near-far head placement to specific dimpling instructions. For a detailed breakdown of these codes, refer to the NAS523 Rivet Identification Guide on Scribd
NAS523 Rivet Identification Guide | PDF | Rivet | Sheet Metal - Scribd
Based on the keyword "nas523 pdf", the search query refers to a specific technical standard used primarily in the aerospace and defense industries.
Here is a detailed write-up on the standard, its applications, and the context of the PDF document.
Design engineers rely on the mechanical properties listed in the NAS523 PDF to calculate clamp loads, torque values, and fatigue resistance. Using an outdated or incorrect version of the standard could cause a structural failure. but for regulated industries
In aerospace, precision is paramount. A rivet that is slightly too short may not form a proper "shop head" (the flattened end created during installation), leading to structural failure. A rivet that is too long might buckle during installation. NAS523 ensures that regardless of the manufacturer, a specific part number will have the exact same dimensions and strength properties.
Issuing Body: Aerospace Industries Association (AIA) / National Aerospace Standards (NAS)
Searching for a specific PDF file might seem trivial, but for regulated industries, having the correct revision of a standard is a matter of legal liability.
Use the following format: Aerospace Industries Association (AIA), “NAS523: Fastener, Captive Washer, Non-Metallic, Assembly, Procurement Specification,” [Revision Date], Washington, D.C.