NAS42 Sleeve Spacers

NAS42, titled "Spacer, Sleeve, Rivet," is a National Aerospace Standard published by the Aerospace Industries Association (AIA). The part is a plain round tube with square ends and no outside flange. Federal supply records catalog it under the item name Spacer, Sleeve, in federal supply class 5365. Its diameter codes cover outside diameters from 3/16 inch to 5/8 inch and nominal inside diameters from .100 inch to .380 inch. Length is set in 1/64 inch steps, with common lengths running from 4/64 inch to 320/64 inch. Its sibling standard, NAS43, covers sleeve spacers for screws and bolts. Emanon quotes NAS42 spacers with CofC and lot traceability, usually in about an hour.

HOW TO READ A NAS42 PART NUMBER

A NAS42 part number has four pieces: the material code, the diameter code, the length dash number and an optional finish code. DD means 2024 aluminum and HT means alloy steel. The diameter code sets the outside and inside diameter from the standard's table. An A or B after the diameter code keeps the bore of the base size with a smaller outside diameter. Sizes 6, 6A and 6B all have a .190 to .196 inch bore, with outside diameters of 3/8, 1/4 and 5/16 inch. The length dash number is the length in 1/64 inch. FC means chemical film, N means grey anodize and A means no finish. On aluminum parts with no finish code, the maker may supply FC or N. Worked example: NAS42DD5-28FC is a 2024 aluminum spacer (DD), diameter 5 (OD .302 to .322 inch, ID .160 to .166 inch), 28/64 = .4375 inch long, with chemical film finish (FC).

MATERIALS AND FINISHES

DD spacers are 2024 aluminum: 2024-T3 tubing to AMS-WW-T-700/3 or 2024-T4 rod to AMS-QQ-A-225/6. Some federal records also list a 62 ksi minimum tensile strength. Code N parts are grey anodized to MIL-A-8625 (now MIL-PRF-8625) Type I. Code FC parts get chemical film to MIL-C-5541 (now MIL-DTL-5541) Class 1A, which makers and federal records show dyed blue. HT spacers are 4130 or 8630 alloy steel. Federal records cite MIL-T-6736 or MIL-T-6732 tubing in condition HT-125, or MIL-S-6758 or MIL-S-6050 bar in condition F, cadmium plated to QQ-P-416 Type 2 Class 2. Every order ships with CofC and lot traceability.

SUPERSEDING SPECIFICATION

The most recent NAS42 edition on record is Revision 11, dated October 31, 2012, and we found no superseding standard. Federal supply records still reference NAS42 parts. If your drawing calls out a specific revision, include it on your RFQ so we can quote to it.