The Bolt,close Tolerance, cataloged under National Stock Number 5306-00-993-1543, is classified within Federal Supply Class 5306 (Bolts) of the Hardware and Abrasives group. The manufacturer of record is Northrop Grumman Systems Corporation. Government technical data includes 25 specifications, cited from the U.S. Government catalog. The record lists 7 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 5 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5306-00-993-1543 |
| Primary Part Number | 51B464-4A1H |
| Item Name | Bolt,close Tolerance |
| FSC / FSG | 5306 / 53 — Bolts |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Surface Finish | 32.0 MICROINCHES THREADS |
| Surface Finish | 32.0 MICROINCHES GRIP |
| Surface Finish | 63.0 MICROINCHES HEAD |
| Head Height | 0.125 INCHES NOMINAL IN |
| Fastener Length | 0.378 INCHES NOMINAL IN |
| Surface Treatment Document and Classification | QQ-P-416,TYPE 2,CLASS 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.316 INCHES MINIMUM IN |
| Hardness Rating | 36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM OVERALL |
| Hole Configuration Style | HEXAGON LONGITUDINAL HOLE |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | HEXAGON |
| Thread Direction | RIGHT-HAND |
| Specification/standard Data | 76823-51B464 MANUFACTURERS STANDARD |
| Grip Length | 0.062 INCHES NOMINAL IN |
| Width Between Flats | 0.438 INCHES NOMINAL IN |
| Grip Diameter | 0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM AND CHROMATE OVERALL |
| Minimum Tensile Strength | 180000 POUNDS PER SQUARE INCH LBS |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | STEEL COMP E4340 OR STEEL COMP 4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OR STEEL COMP 6150 OVERALL |
| Hole Quantity | 3 |
| Thread Series Designator | UNF |
| Hole Type | DRILLED |
| Hole Diameter | 0.046 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 |
|---|---|
| 51B464-4A1H | Hi-Shear Corporation (USA) |
| 51B464-4A1H | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| 51B464-4A1H | Howmet Global Fastening Systems Inc (USA) |
| 51B464-4A1H | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| 51B464-4A1H | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| 51B464-4A1H PRIMARY | Northrop Grumman Systems Corporation (USA) |
| 51B464-4A1H | Huck International, Inc (USA) |
| Reference | Meaning |
|---|---|
| 51B464-4A1H | 5/9 Secondary reference U.S. Government activity |
| 51B464-4A1H | 5/9 Secondary reference U.S. Government activity |
| 51B464-4A1H | 5/2 Secondary reference U.S. Government activity |
| 51B464-4A1H | 5/9 Secondary reference Northrop Grumman Technical Services, Inc. Dba Defense Systems Sector |
| 51B464-4A1H | 3/9 Design control — primary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Is Div Northrop Grumman Aeronautics Systems |
NSN 5306-00-993-1543 is a Bolt,close Tolerance, manufactured by Northrop Grumman Systems Corporation, classified under FSC 5306, Bolts. Status: active.
NSN 5306-00-993-1543 has 7 manufacturer part numbers on file: 51B464-4A1H (Hi-Shear Corporation), 51B464-4A1H (Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company), 51B464-4A1H (Howmet Global Fastening Systems Inc), 51B464-4A1H (Sps Technologies Llc Dba PB Fasteners Div PB Fasteners), 51B464-4A1H (Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc) and 2 more.
Key specifications for 51B464-4A1H: Surface Finish: 32.0 MICROINCHES THREADS; Surface Finish: 32.0 MICROINCHES GRIP; Surface Finish: 63.0 MICROINCHES HEAD; Head Height: 0.125 INCHES NOMINAL IN. 25 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.