: The top two sheets are dimpled, while the third underlying sheet is countersunk.
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A single NAS523 cross symbol tells a technician or mechanic exactly: What type of rivet to use (head style and specification) What material the rivet must be made of The diameter of the rivet The total length of the rivet Which side the manufactured head should be on Dimpling or countersinking requirements for the skin panels Decoding the NAS523 Four-Quadrant Symbol The core of the NAS523 system is a simple cross (
2024 aluminum alloy, identified by two raised dashes; known as "icebox rivets," they must be heat-treated and refrigerated before use. D: 2017 aluminum alloy, marked with a raised dot. Installation Specifications nas523 rivet code pdf
NAS523 Rivet Code is a symbolic identification system used in aviation diagrams and engineering drawings to communicate fastener specifications clearly through a four-quadrant "crosshair" symbol. NAS523 Quadrant Breakdown
1. Top Quadrant: Rivet Part Number (Material and Head Style)
The NAS523 specification is periodically revised to incorporate updates and refinements. The most current version is , which consists of 48 pages and was published on June 30, 2014. Previous versions include NAS523-2013 (Revision 30) and NAS523-2007 (Revision 29). : The top two sheets are dimpled, while
Direct conversions between military standards (MS), National Aerospace Standards (NAS), and Army-Navy (AN) part numbers. Best Practices for Shop Use
4. Southeast (SE) Quadrant: Fastener Length and Welding Alternates
The NAS523 code is a standardized system defined by National Aerospace Standards (NAS) to represent rivet specifications on engineering drawings using a simple cross-shaped symbol. Instead of writing out lengthy part numbers, materials, lengths, and locations for every single fastener, engineers use this universal shorthand. D: 2017 aluminum alloy, marked with a raised dot
A code displaying:
Let’s look at a common part number: