The Packing Nut, cataloged under National Stock Number 4730-00-005-5521, is classified within Federal Supply Class 4730 (Hose, Pipe, Tube, Lubrication, and Railing Fittings) of the Pipe, Tubing, Hose, and Fittings group. The manufacturer of record is Northrop Grumman Systems Corporation. Government technical data includes 10 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4730-00-005-5521 |
| Primary Part Number | A51K56511-3 |
| Item Name | Packing Nut |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Thread Length | 0.540 INCHES NOMINAL IN |
| Material Document and Classification | AMS 5659 ASSN STD SINGLE MATERIAL RESPONSE |
| Thread Direction | RIGHT-HAND |
| Casehardening Indicator | NOT CASEHARDENED |
| Thread Size | 3.000-16 |
| Screw Thread Series Designator | UNIFIED NATIONAL JOINT (UNJ) |
| Surface Treatment | LACQUER |
| Thread Class | 3B |
| Screw Thread Location | INTERNAL |
| Material | STEEL COMP XM-12 |
| 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 |
|---|---|
| A51K56511-3 | Northrop Grumman Systems Corporation (USA) |
| Reference | Meaning |
|---|---|
| A51K56511-3 | 3/2 Design control — primary reference U.S. Government activity |
| A51K56511-3 | 5/9 Secondary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems |
| A51K56511-3 | 5/9 Secondary reference Northrop Grumman Systems Corporation |
NSN 4730-00-005-5521 is a Packing Nut, manufactured by Northrop Grumman Systems Corporation, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
NSN 4730-00-005-5521 has 1 manufacturer part number on file: A51K56511-3 (Northrop Grumman Systems Corporation).
Key specifications for A51K56511-3: Thread Length: 0.540 INCHES NOMINAL IN; Material Document and Classification: AMS 5659 ASSN STD SINGLE MATERIAL RESPONSE; Thread Direction: RIGHT-HAND; Casehardening Indicator: NOT CASEHARDENED. 10 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.