: Specifies the shank diameter, calculated uniformly in 1/32-inch increments . A value of 4 indicates a 4/32” (1/8”) diameter. This quadrant also houses the letters N (Near Side) or F (Far Side) to inform the technician which side of the sheet metal receives the manufactured head.
For example, the diameter code consists of one to two digits—for rivets, this is measured in 1/32nd-inch increments.
The upper-left quadrant identifies the basic part number series (such as or MS military standard specifications) and the precise chemical alloy from which the fastener is made.
The code specifically applies to fasteners that are permanently deformed during installation, meaning they must be destroyed to be removed. Locating Points: nas523 pdf top
: Top aerospace hardware manufacturers (such as Cherry Aerospace, Alcoa, or Arconic) publish comprehensive product catalogs. These catalogs often contain an appendix with the best, cleanest NAS523 decoding charts available for free download. Best Practices for Using NAS523 Standards in the Field
/ DD : 2024-T4 Aluminum Alloy (Icebox rivets, raised double dash).
By keeping a copy of the NAS523 PDF on your local computer, you ensure that even if your internet goes down, you have the instructions needed to fix your local network storage. : Specifies the shank diameter, calculated uniformly in
The NE quadrant determines the structural thickness of the rivet shank and dictates which side of the aircraft structure the manufactured head must reside.
For engineers, inspectors, and technicians working with aerospace structures, the is more than a document—it‘s a working tool used daily in design offices, factory floors, and hangars worldwide. Knowing where to find the top (most current, complete, and authoritative) version is essential for professional practice.
“Review the fastener manufacturer‘s design criteria before incorporating the fasteners into your design.” For example, the diameter code consists of one
The standard is regularly updated, with Revision 31 published on 06/30/2014, available through reputable standards providers. Decoding the NAS523 Symbol: A Top-Down Approach
: For countersunk flush fasteners, length covers the tip of the tail to the top surface of the head. Universal-head fasteners measure only from the bottom flat of the head to the tail tip. Core Formulas for Aircraft Structural Quality Assurance