NAS77 Flanged Bushings

NAS77 is a National Aerospace Standard published by the Aerospace Industries Association (AIA). It covers flanged press fit bushings in steel, CRES, aluminum bronze and beryllium copper, and dates back to at least 1944. The part is a solid sleeve with an external flange on one end. Federal records give the flange as .057 to .062 inch thick. Catalog and federal records show bore sizes from .190 inch (size 3) up to 1.500 inch (size 24). Federal supply records catalog NAS77 parts under the item name Bushing, Sleeve, with older listings in supply class 3120 and newer ones in class 5365. Emanon quotes NAS77 bushings with CofC and lot traceability, and quotes usually come back in about an hour.

HOW TO READ A NAS77 PART NUMBER

A NAS77 part number is the basic number, a material letter, a size code and a length code. In federal supply records, no letter means alloy steel, A is aluminum bronze, B is beryllium copper and C is CRES. The size code sets the bore in sixteenths of an inch, so 4 is .250. Size 3 is the exception, with a .190 bore. The length code is in .010 inch steps, so -025 is .25 inch. Older records may write -023 as -23. Some part numbers end in a finish suffix such as P, N or A. Send the part number exactly as your drawing shows it, suffix included. Worked example: NAS77A6-023P is an aluminum bronze bushing (A), size 6, with a .3750 to .3765 inch bore and a .5006 to .5013 inch body OD. Its federal record lists a cadmium finish and a .282 to .297 inch overall length.

MATERIALS AND FINISHES

NAS77 parts with no material letter are 4130 or 8630 alloy steel to MIL-S-6758 or MIL-S-6050, cadmium plated to QQ-P-416 Type II. A parts are aluminum bronze: older records cite copper alloy 642 to QQ-C-465, newer ones copper alloy 630 to AMS 4640 or ASTM B150. B parts are beryllium copper, alloy 170, 172 or 173, to ASTM B196 or B197, with older records citing QQ-C-530. C parts are 17-4PH CRES to AMS 5643, passivated or cadmium plated depending on the part number. The standard also references NAS4006 aluminum coating, which federal records show on the body OD and flange of parts ending in A. Every order ships with CofC and lot traceability.

SUPERSEDING SPECIFICATION

NAS77 is active at Revision 16, dated December 31, 2025, and we found no record of it being superseded or cancelled. The previous edition is dated March 31, 2016. If your drawing calls out a specific revision, include it on your RFQ so we can quote to it.