The Washer,recessed, cataloged under National Stock Number 5310-00-004-7046, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Northrop Grumman Systems Corporation. Government technical data includes 13 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-00-004-7046 |
| Primary Part Number | A51B21644-15 |
| Item Name | Washer,recessed |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Heat Treatment | QUENCHED AND TEMPERED |
| Hardness Rating | 46.0 ROCKWELL C MINIMUM AND 49.0 ROCKWELL C MAXIMUM |
| Style Designator | RECESSED |
| Material Document and Classification | MIL-S-8949 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Outside Diameter | 1.750 INCHES NOMINAL IN |
| Recess Depth | 0.094 INCHES NOMINAL IN |
| Material Thickness | 0.187 INCHES NOMINAL IN |
| Recess Diameter | 0.604 INCHES MINIMUM AND 0.620 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM OVERALL |
| Test Data Document | 81349-MIL-I-6868 SPECIFICATION (INCLUDES ENGINEERING TYPE BULLETINS, BROCHURES,ETC., THAT REFLECT SPECIFICATION TYPE DATA IN SPECIFICATION FORMAT; EXCLUDES COMMERCIAL CATALOGS, INDUSTRY DIRECTORIES, AND SIMILAR TRADE PUBLICATIONS, REFLECTING GENERAL TYPE DATA ON CERTAIN ENVIRONMENTAL AND PERFORMANCE REQUIREMENTS AND TEST CONDITIONS THAT ARE SHOWN AS "TYPICAL", "AVERAGE", "NOMINAL", ETC.). |
| Material | STEEL OVERALL |
| Hole Diameter | 0.514 INCHES MINIMUM AND 0.523 INCHES MAXIMUM IN |
| Recess Angle | 90.0 DEGREES NOMINAL |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| A51B21644-15 PRIMARY | Northrop Grumman Systems Corporation (USA) |
| Reference | Meaning |
|---|---|
| A51B21644-15 | 3/9 Design control — primary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems |
| A51B21644-15 | 5/9 Secondary reference Northrop Grumman Systems Corporation |
NSN 5310-00-004-7046 is a Washer,recessed, manufactured by Northrop Grumman Systems Corporation, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-004-7046 has 1 manufacturer part number on file: A51B21644-15 (Northrop Grumman Systems Corporation).
Key specifications for A51B21644-15: Overall Height: 0.187 INCHES NOMINAL IN; Heat Treatment: QUENCHED AND TEMPERED; Hardness Rating: 46.0 ROCKWELL C MINIMUM AND 49.0 ROCKWELL C MAXIMUM; Style Designator: RECESSED. 13 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.