The "Top" position of the NAS523 symbol is the most critical. It typically indicates the or the specific material and type of the fastener.
Using the wrong rivet material can lead to galvanic corrosion or structural failure. nas523 pdf top
Indicates the rivet diameter in 1/32-inch increments. The "Top" position of the NAS523 symbol is the most critical
It helps mechanics select the correct bucking bars and rivet sets for the job. Where to Find NAS523 Documentation nas523 pdf top