code is a symbolic system used on aviation blueprints and technical drawings to specify rivet installation details within a single four-quadrant "crosshair" symbol. NAS523 Quadrant Breakdown
Aircraft structural assembly relies heavily on precision, standardization, and absolute traceability. In aerospace manufacturing and repair, rivets are the literal fasteners holding structures together under immense stress.
The symbol consists of a central cross whose intersection marks the exact location of the rivet on the drawing. Information is coded into four quadrants around this intersection: Information Provided Upper Left Rivet Identity (Part Number & Alloy) BJ (MS20470AD), BB (MS20426AD) NE Upper Right Diameter and Manufacturing Head Location 3N (3/32" diameter, head on Near side) SW Lower Left Hole Preparation (Dimple/Countersink) D (Dimple), C (Countersink), D2C SE Lower Right Rivet Length -5 (5/16"), -6 (3/8") Deep Dive into the Quadrants 1. Northwest (NW): Rivet Identity nas523 rivet code pdf
The upper right quadrant contains:
The most common "AD" rivet for structural repairs. 2024 (Raised Dot): High-strength "DD" rivets. 5056 (Raised Cross): Used for aluminum-magnesium alloys. 2. Head Style and Type code is a symbolic system used on aviation
(Note: Exact letter combinations vary based on the specific revision of the standard and the aircraft manufacturer's internal process sheets, which map NAS523 characters to specific part numbers like Boeing or Airbus standards). The Numbers: Size Dimensions
The unit of measurement for the diameter code depends on the fastener type: The symbol consists of a central cross whose
Understanding NAS523 Rivet Code PDF: A Comprehensive Guide
Typically contains the rivet part number or manufacturer code.