The Screw,close Tolerance, cataloged under National Stock Number 5305-01-261-1893, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Sps Technologies Llc Dba PB Fasteners Div PB Fasteners. Government technical data includes 17 specifications, cited from the U.S. Government catalog. The record lists 5 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through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 5305-01-261-1893 |
| Primary Part Number | 51B334-8X |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners |
| Status | ACTIVE |
| Fastener Length | 0.806 INCHES MINIMUM AND 0.826 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-416,TYPE 2,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.306 INCHES MINIMUM AND 0.326 INCHES MAXIMUM 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 | 0.495 INCHES MINIMUM AND 0.505 INCHES MAXIMUM IN |
| Grip Diameter | 0.264 INCHES MINIMUM AND 0.265 INCHES MAXIMUM IN |
| Surface Treatment | CHROMIUM OVERALL |
| 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 4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OVERALL |
| Thread Series Designator | UNJC |
| Head Diameter | 0.499 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 | X |
| Part Number | Manufacturer |
|---|---|
| 51B334-8X | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| 51B334-8X | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| 51B334-8X | Howmet Global Fastening Systems Inc (USA) |
| 51B334-8X | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| 51B334-8X | Hi-Shear Corporation (USA) |
| Reference | Meaning |
|---|---|
| 51B334-8X | 5/2 Secondary reference U.S. Government activity |
| 51B334-8X | C/1 Advisory reference — outside the item-of-supply concept Northrop Grumman Technical Services, Inc. Dba Defense Systems Sector |
| 51B334-8X | 3/9 Design control — primary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Is Div Northrop Grumman Aeronautics Systems |
| 51B334-8X | 5/2 Secondary reference U.S. Government activity |
NSN 5305-01-261-1893 is a Screw,close Tolerance, manufactured by Sps Technologies Llc Dba PB Fasteners Div PB Fasteners, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-261-1893 has 5 manufacturer part numbers on file: 51B334-8X (Sps Technologies Llc Dba PB Fasteners Div PB Fasteners), 51B334-8X (Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company), 51B334-8X (Howmet Global Fastening Systems Inc), 51B334-8X (Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc), 51B334-8X (Hi-Shear Corporation).
Key specifications for 51B334-8X: Fastener Length: 0.806 INCHES MINIMUM AND 0.826 INCHES MAXIMUM IN; Surface Treatment Document and Classification: QQ-P-416,TYPE 2,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL; Thread Length: 0.306 INCHES MINIMUM AND 0.326 INCHES MAXIMUM 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. 17 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.