The Screw,close Tolerance, cataloged under National Stock Number 5305-01-261-1901, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Howmet Global Fastening Systems Inc. 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through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 5305-01-261-1901 |
| Primary Part Number | 51B335-9X |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Howmet Global Fastening Systems Inc |
| Status | ACTIVE |
| Fastener Length | 0.928 INCHES MINIMUM AND 0.948 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-416,TYPE 2,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.365 INCHES MINIMUM AND 0.385 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 | 0.312 INCHES IN |
| Head Style | FLAT COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Grip Length | 0.553 INCHES MINIMUM AND 0.573 INCHES MAXIMUM IN |
| Grip Diameter | 0.326 INCHES MINIMUM AND 0.327 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 | 24 |
| Material | STEEL COMP 4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OVERALL |
| Thread Series Designator | UNJC |
| Head Diameter | 0.626 INCHES MINIMUM AND 0.635 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 |
|---|---|
| 51B335-9X | Howmet Global Fastening Systems Inc (USA) |
| 51B335-9X | Hi-Shear Corporation (USA) |
| 51B335-9X | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| 51B335-9X | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| 51B335-9X | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| Reference | Meaning |
|---|---|
| 51B335-9X | C/1 Advisory reference — outside the item-of-supply concept Northrop Grumman Technical Services, Inc. Dba Defense Systems Sector |
| 51B335-9X | 3/9 Design control — primary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Is Div Northrop Grumman Aeronautics Systems |
| 51B335-9X | 5/2 Secondary reference U.S. Government activity |
| 51B335-9X | 5/2 Secondary reference U.S. Government activity |
NSN 5305-01-261-1901 is a Screw,close Tolerance, manufactured by Howmet Global Fastening Systems Inc, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-261-1901 has 5 manufacturer part numbers on file: 51B335-9X (Howmet Global Fastening Systems Inc), 51B335-9X (Hi-Shear Corporation), 51B335-9X (Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc), 51B335-9X (Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company), 51B335-9X (Sps Technologies Llc Dba PB Fasteners Div PB Fasteners).
Key specifications for 51B335-9X: Fastener Length: 0.928 INCHES MINIMUM AND 0.948 INCHES MAXIMUM IN; Surface Treatment Document and Classification: QQ-P-416,TYPE 2,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL; Thread Length: 0.365 INCHES MINIMUM AND 0.385 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.