This article provides an in-depth analysis of the NAS523 coding system, breaking down how to read the charts, what the characters signify, and why this standard remains a pillar of the aviation industry.

The is more than a table; it is a safety matrix. Using the wrong code on a landing gear attachment or a flight control hinge point is a catastrophic failure waiting to happen.

A complete aerospace rivet code follows a pattern. For a NAS523-compliant rivet, the part number is rarely just “NAS523.” Instead, you will see codes like:

To effectively use the chart, you must decode the part number stamped on the rivet head or listed in the blueprint. The standard format is:

The length of the rivet is indicated here in . For example, a "-6" indicates a length of 6/16" (or 3/8"). It may also indicate if spot welding is an acceptable alternative. Common Rivet Head Markings & Materials

stands for National Aerospace Standard . These standards are managed by the Aerospace Industries Association (AIA) to ensure uniformity in the manufacturing and procurement of aerospace components.

NAS523-4-08 is a 1/8" diameter rivet that is 1/2" long.

Indicates length in 1/16" increments (e.g., a "-6" means a 3/8" long rivet). Common NAS523 Letter Codes

In the NAS523 specification, This code directly correlates to the minimum double-shear strength of the rivet in pounds.

: The length defines only the shank, not including the head. Protrusion Rule