National Stock Number
5310-00-521-8731
National Stock Number (NSN) 5310-00-521-8731, or NIIN 005218731, (washer,flat) was assigned January 1, 1963 in the Federal Logistics Information System (FLIS). This NIIN is Available for Manual Assignment. This NSN does not replace any other NSNs.
There are 4 manufacturer part numbers associated with this NSN. 2 of those part number(s) are considered obsolete. The manufacturer part numbers were originally supplied by one supplier. Today, there are no suppliers listed as an Active supplier for this NSN. Of the active suppliers, there are no suppliers that are deemed design controlled or valid supply parts.
This part number has not been procured by the US Government in over 5 years.
Based on a planned procurement review by the Primary Inventory Control Activity (PICA) on Mar 02, 2006, this NSN's acquisition method was noted as: Suitable for Competitive Acquisition. (Potential sources shall include dealers/distributors.) The Government has unlimited rights to the technical data, and the data package is complete. Valid AMCs: 1 and 2.
This NSN is assigned to Item Name Code (INC) 13393. [A WASHER HAVING A CENTRALLY LOCATED HOLE WITH A SOLID OR LAMINATED CROSS-SECTION AND TWO FLAT PARALLEL BEARING SURFACES. THE HOLE MUST BE 75 PERCENT OR LESS THAN THE LARGEST DIMENSION AND THE BEARING SURFACE FINISH IS GREATER THAN 32 MICROINCH (0.8 MICROMETER). THE THICKNESS CANNOT EXCEED 25 PERCENT OF THE LARGEST OUTSIDE DIMENSION. WHEN THE LARGEST OUTSIDE DIMENSION IS LESS THAN 1/4 INCH OR 6MM, THE THICKNESS MUST BE 0.006 INCHES (0.15MM) OR GREATER AND FOR ITEMS 1/4 INCH (6MM) OR LARGER, THE THICKNESS MUST BE 0.016 INCHES (0.4MM) OR GREATER. THE MAXIMUM TOLERANCE IS APPLIED TO DIMENSIONS AND USED AS A DETERMINING FACTOR. ITEMS WITH SEPARABLE LAMINATION USE SHIM. FOR ITEMS FABRICATED FROM CERAMIC OR ELECTRICALLY RATED MATERIALS BY SPECIFICATION OR INDUSTRY STANDARDS USE INSULATOR (1), WASHER. EXCLUDES:DISK, VALVE, GRAPHITE IMPREGNATED AND LUBRICATED ITEMS.]. This item does not have a nuclear hardened feature or any other critical feature such as tolerance, fit restriction or application. There is no data in the HMIRS and the NSN is in an FSC not generally suspected of containing hazardous materials. NSN 5310005218731 contains an unknown precious metal.
This NSN is associated to Schedule B 7318220000: washers other than lock washers, iron or steel. The Schedule B End Use is listed as finished metal shapes. NAICS classification category 332722: bolt, nut, screw, rivet, and washer manufacturing.
This information was last updated on Aug 01, 2025.