Nas523 Pdf Top Link
Indicates the rivet diameter in 1/32-inch increments.
The "Top" position of the NAS523 symbol is the most critical. It typically indicates the or the specific material and type of the fastener. nas523 pdf top
When you download a NAS523 PDF, you will find a table of letter codes that correspond to specific alloys. Some of the most common include: 2117 Aluminum Alloy (The most common structural rivet). D: 2017 Aluminum Alloy. DD: 2024 Aluminum Alloy. Indicates the rivet diameter in 1/32-inch increments
While many online summaries exist, the official is essential for several reasons: nas523 pdf top
The code clarifies if the rivet is a universal head (protruding) or countersunk (flush).
It looks like a cross (+) with information in the four quadrants.