The Screw,close Tolerance, cataloged under National Stock Number 5305-01-047-4001, 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 22 specifications, cited from the U.S. Government catalog. The record lists 6 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-047-4001 |
| Primary Part Number | 51B334-31H |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Surface Finish | 32.0 MICROINCHES GRIP |
| Fastener Length | 2.238 INCHES MINIMUM AND 2.285 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-416,TYPE 2 CL 2 FED SPEC 1ST TREATMENT RESPONSE OR NAS 672 ASSN STD 2ND TREATMENT RESPONSE OVERALL |
| Thread Length | 0.290 INCHES MINIMUM AND 0.357 INCHES MAXIMUM IN |
| Hardness Rating | 39.0 ROCKWELL C MINIMUM AND 43.0 ROCKWELL C MAXIMUM OVERALL |
| Shank Unthreaded Hole Diameter | 0.066 INCHES MINIMUM AND 0.086 INCHES MAXIMUM FIRST HOLE IN |
| Material Document and Classification | MIL-S-5000 MIL SPEC 1ST MATERIAL RESPONSE OR MIL-S-5626 MIL SPEC 2ND MATERIAL RESPONSE OR MIL-S-6049 MIL SPEC 3RD MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | FLAT COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Grip Length | 1.928 INCHES MINIMUM AND 1.948 INCHES MAXIMUM IN |
| Grip Diameter | 0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM AND CHROMATE OR CADMIUM OVERALL |
| Minimum Tensile Strength | 180000 POUNDS PER SQUARE INCH LBS |
| Internal Drive Style | OFFSET CRUCIFORM (TORQUE SET) |
| Countersink Angle | 100.0 DEGREES NOMINAL |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | STEEL COMP E4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Distance From Head Largest Bearing Surface to Shank Hole Center | 2.112 INCHES MINIMUM AND 2.179 INCHES MAXIMUM FIRST HOLE IN |
| Head Diameter | 0.451 INCHES MINIMUM AND 0.507 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 | F |
| Part Number | Manufacturer |
|---|---|
| 51B334-31H PRIMARY | Northrop Grumman Systems Corporation (USA) |
| 51B334-31H | Howmet Global Fastening Systems Inc (USA) |
| 51B334-31H | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| 51B334-31H | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| 51B334-31H | Hi-Shear Corporation (USA) |
| 51B334-31H | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| Reference | Meaning |
|---|---|
| 51B334-31H | 3/9 Design control — primary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Is Div Northrop Grumman Aeronautics Systems |
| 51B334-31H | 5/2 Secondary reference U.S. Government activity |
| 51B334-31H | 5/9 Secondary reference Northrop Grumman Technical Services, Inc. Dba Defense Systems Sector |
| 51B334-31H | 5/2 Secondary reference U.S. Government activity |
NSN 5305-01-047-4001 is a Screw,close Tolerance, manufactured by Northrop Grumman Systems Corporation, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-047-4001 has 6 manufacturer part numbers on file: 51B334-31H (Northrop Grumman Systems Corporation), 51B334-31H (Howmet Global Fastening Systems Inc), 51B334-31H (Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc), 51B334-31H (Sps Technologies Llc Dba PB Fasteners Div PB Fasteners), 51B334-31H (Hi-Shear Corporation) and 1 more.
Key specifications for 51B334-31H: Surface Finish: 32.0 MICROINCHES GRIP; Fastener Length: 2.238 INCHES MINIMUM AND 2.285 INCHES MAXIMUM IN; Surface Treatment Document and Classification: QQ-P-416,TYPE 2 CL 2 FED SPEC 1ST TREATMENT RESPONSE OR NAS 672 ASSN STD 2ND TREATMENT RESPONSE OVERALL; Thread Length: 0.290 INCHES MINIMUM AND 0.357 INCHES MAXIMUM IN. 22 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.