The Screw,close Tolerance, cataloged under National Stock Number 5305-01-076-6318, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company. 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through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 5305-01-076-6318 |
| Primary Part Number | 51B581-5-22H |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company |
| Status | ACTIVE |
| Surface Finish | 32.0 MICROINCHES GRIP |
| Fastener Length | 1.734 INCHES MINIMUM AND 1.781 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-416 TY 2 CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.349 INCHES MINIMUM AND 0.416 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 | 0.312 INCHES IN |
| Head Style | FLAT COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Grip Length | 1.365 INCHES MINIMUM AND 1.385 INCHES MAXIMUM IN |
| Grip Diameter | 0.3110 INCHES MINIMUM AND 0.3120 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM AND CHROMATE OVERALL |
| Minimum Tensile Strength | 180000 POUNDS PER SQUARE INCH LBS |
| Internal Drive Style | OFFSET CRUCIFORM (TORQUE SET) |
| Countersink Angle | 99.5 DEGREES MINIMUM AND 100.5 DEGREES MAXIMUM |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 24 |
| Material | STEEL COMP E4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OVERALL |
| Thread Series Designator | UNF |
| Distance From Head Largest Bearing Surface to Shank Hole Center | 1.615 INCHES MINIMUM AND 1.662 INCHES MAXIMUM FIRST HOLE IN |
| Head Diameter | 0.469 INCHES MINIMUM AND 0.474 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 |
|---|---|
| 51B581-5-22H | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| 51B581-5-22H | Howmet Global Fastening Systems Inc (USA) |
| 51B581-5-22H PRIMARY | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| 51B581-5-22H | Huck International, Inc (USA) |
| 51B581-5-22H | Hi-Shear Corporation (USA) |
| 51B581-5-22H | Tactair Fluid Controls Inc (USA) |
| Reference | Meaning |
|---|---|
| 51B581-5-22H | 5/9 Secondary reference Grimes Aerospace Company |
| 51B581-5-22H | 3/9 Design control — primary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Is Div Northrop Grumman Aeronautics Systems |
| 51B581-5-22H | 5/2 Secondary reference U.S. Government activity |
| 51B581-5-22H | C/1 Advisory reference — outside the item-of-supply concept Northrop Grumman Technical Services, Inc. Dba Defense Systems Sector |
NSN 5305-01-076-6318 is a Screw,close Tolerance, manufactured by Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-076-6318 has 6 manufacturer part numbers on file: 51B581-5-22H (Sps Technologies Llc Dba PB Fasteners Div PB Fasteners), 51B581-5-22H (Howmet Global Fastening Systems Inc), 51B581-5-22H (Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company), 51B581-5-22H (Huck International, Inc), 51B581-5-22H (Hi-Shear Corporation) and 1 more.
Key specifications for 51B581-5-22H: Surface Finish: 32.0 MICROINCHES GRIP; Fastener Length: 1.734 INCHES MINIMUM AND 1.781 INCHES MAXIMUM IN; Surface Treatment Document and Classification: QQ-P-416 TY 2 CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL; Thread Length: 0.349 INCHES MINIMUM AND 0.416 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.