NAS501 Hex Head Bolts

NAS501 is a National Aerospace Standard from the Aerospace Industries Association (AIA) for hex head tension bolts in stabilized, non-magnetic corrosion resistant steel (CRES), with a minimum ultimate tensile strength of 85 ksi. Federal supply records catalog these parts under the item name Bolt, Machine. Threads are UNF, class 3A, and the hex head is finished. The standard covers plain and drilled heads, with or without a drilled shank, in thread sizes from 10-32 up to 1-1/4-12. The standard is listed as inactive, but federal supply records still reference NAS501 parts, and Emanon quotes them with CofC and lot traceability, usually in about an hour.

HOW TO READ A NAS501 PART NUMBER

A NAS501 part number is the standard number, a diameter code, a dash and a length code, with letters added for some versions. The diameter code sets the thread size: 3 is 10-32, 4 is 1/4-28, 5 is 5/16-24, 6 is 3/8-24, 7 is 7/16-20, 8 is 1/2-20, 9 is 9/16-18, 10 is 5/8-18, 12 is 3/4-16, 16 is 1-14 and 20 is 1-1/4-12. Each length code has its own grip and overall length in the standard's table. An H after the diameter code means the head is drilled for safety wire, as on NAS501-3H5A. A trailing A means the shank is not drilled. Without the A, the shank is drilled for a cotter pin. Example: NAS501-3-6A is a 10-32 UNF bolt with a grip of 0.359 to 0.391 inch and an overall length of 0.765 to 0.812 inch, with an undrilled shank. NAS501-3-6, the same size without the A, has its shank drilled for a cotter pin.

MATERIALS AND FINISHES

NAS501 bolts are made from CRES type 321 or type 347, two stabilized stainless grades, to AMS 5645 or AMS 5646, and the standard describes them as non-magnetic. Some older federal supply records cite QQ-S-763. Bolts are passivated per QQ-P-35 or AMS2700. Some records cite AS7473 as the procurement specification, except for tensile strength, which follows the NAS501 table. The minimum ultimate tensile strength is 85 ksi.

SUPERSEDING SPECIFICATION

NAS501 is listed as inactive. The latest edition is dated October 29, 2010, and no replacement standard has been named. Federal supply records still reference NAS501 parts. If your drawing calls out a specific edition, include it on your RFQ so we can quote to it.