The Washer,key, cataloged under National Stock Number 5310-00-003-6542, 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 15 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 5310-00-003-6542 |
| Primary Part Number | A51G20121-13 |
| Item Name | Washer,key |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Internal Straight Key Width | 0.059 INCHES MINIMUM AND 0.065 INCHES MAXIMUM IN |
| Distance From Centerline to Top of Internal Key | 0.193 INCHES MINIMUM AND 0.205 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | MIL-C-8837,TYPE2,CLASS1 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Distance From Centerline to Inside of Prebent Key | 0.351 INCHES MINIMUM AND 0.367 INCHES MAXIMUM IN |
| External Prebent Key Length | 0.045 INCHES MINIMUM AND 0.055 INCHES MAXIMUM IN |
| Overall Distance Including Keys | 0.738 INCHES MINIMUM AND 0.764 INCHES MAXIMUM IN |
| Hardness Rating | 33.0 ROCKWELL C MINIMUM AND 37.0 ROCKWELL C MAXIMUM |
| Style Designator | KEY |
| Material Document and Classification | MIL-S-18729 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Material Thickness | 0.038 INCHES NOMINAL 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.). |
| External Prebent Key Width | 0.105 INCHES MINIMUM AND 0.115 INCHES MAXIMUM IN |
| Material | STEEL COMP 4130 OVERALL |
| Hole Diameter | 0.470 INCHES MINIMUM AND 0.480 INCHES MAXIMUM IN |
| 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 |
|---|---|
| A51G20121-13 PRIMARY | Northrop Grumman Systems Corporation (USA) |
| Reference | Meaning |
|---|---|
| A51G20121-13 | 5/9 Secondary reference Northrop Grumman Systems Corporation |
| A51G20121-13 | 3/9 Design control — primary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems |
NSN 5310-00-003-6542 is a Washer,key, manufactured by Northrop Grumman Systems Corporation, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-003-6542 has 1 manufacturer part number on file: A51G20121-13 (Northrop Grumman Systems Corporation).
Key specifications for A51G20121-13: Internal Straight Key Width: 0.059 INCHES MINIMUM AND 0.065 INCHES MAXIMUM IN; Distance From Centerline to Top of Internal Key: 0.193 INCHES MINIMUM AND 0.205 INCHES MAXIMUM IN; Surface Treatment Document and Classification: MIL-C-8837,TYPE2,CLASS1 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL; Distance From Centerline to Inside of Prebent Key: 0.351 INCHES MINIMUM AND 0.367 INCHES MAXIMUM IN. 15 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.