The Screw,shoulder, cataloged under National Stock Number 5305-01-009-3973, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Northrop Grumman Systems Corporation. Government technical data includes 21 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 5305-01-009-3973 |
| Primary Part Number | A51B25618-11 |
| Item Name | Screw,shoulder |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Width Across Flats | 0.500 INCHES NOMINAL IN |
| Head Height | 0.625 INCHES NOMINAL IN |
| Fastener Length | 2.060 INCHES NOMINAL IN |
| Shoulder Length | 0.985 INCHES MINIMUM AND 0.995 INCHES MAXIMUM FIRST SHOULDER IN |
| Surface Treatment Document and Classification | MIL-C-8837 TY2 CL 1 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Shoulder Diameter | 0.6150 INCHES MINIMUM AND 0.6156 INCHES MAXIMUM FIRST SHOULDER IN |
| Thread Length | 1.070 INCHES NOMINAL IN |
| Shoulder Shape | ROUND FIRST SHOULDER |
| Hardness Rating | 39.0 ROCKWELL C MINIMUM AND 42.0 ROCKWELL C MAXIMUM OVERALL |
| Material Document and Classification | MIL-S-8844,CLASS 1 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.500 INCHES IN |
| Head Style | BEVEL-CONICAL |
| Thread Direction | RIGHT-HAND |
| Surface Treatment | CADMIUM AND CHROMATE OVERALL |
| Minimum Tensile Strength | 180000 POUNDS PER SQUARE INCH LBS |
| Internal Drive Style | HEXAGON |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 20 |
| Material | STEEL COMP 4340 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 1.045 INCHES NOMINAL 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 |
|---|---|
| A51B25618-11 PRIMARY | Northrop Grumman Systems Corporation (USA) |
| Reference | Meaning |
|---|---|
| A51B25618-11 | 5/9 Secondary reference Northrop Grumman Systems Corporation |
| A51B25618-11 | 3/9 Design control — primary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems |
| A51B25564-13 | C/1 Advisory reference — outside the item-of-supply concept Northrop Grumman Systems Corporation |
NSN 5305-01-009-3973 is a Screw,shoulder, manufactured by Northrop Grumman Systems Corporation, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-009-3973 has 1 manufacturer part number on file: A51B25618-11 (Northrop Grumman Systems Corporation).
Key specifications for A51B25618-11: Width Across Flats: 0.500 INCHES NOMINAL IN; Head Height: 0.625 INCHES NOMINAL IN; Fastener Length: 2.060 INCHES NOMINAL IN; Shoulder Length: 0.985 INCHES MINIMUM AND 0.995 INCHES MAXIMUM FIRST SHOULDER IN. 21 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.