The Bolt,shoulder, cataloged under National Stock Number 5306-00-973-5594, 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 18 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5306-00-973-5594 |
| Primary Part Number | A51B21645-11 |
| Item Name | Bolt,shoulder |
| FSC / FSG | 5306 / 53 — Bolts |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Head Height | 0.210 INCHES NOMINAL IN |
| Fastener Length | 1.289 INCHES NOMINAL IN |
| Shoulder Length | 0.874 INCHES MINIMUM AND 0.884 INCHES MAXIMUM FIRST SHOULDER IN |
| Surface Treatment Document and Classification | MIL-C-8837,TY 2 CL 1 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Shoulder Diameter | 0.3733 INCHES MINIMUM AND 0.3742 INCHES MAXIMUM FIRST SHOULDER IN |
| Thread Length | 0.405 INCHES MINIMUM AND 0.415 INCHES MAXIMUM IN |
| Shoulder Shape | ROUND FIRST SHOULDER |
| Hardness Rating | 46.0 ROCKWELL C MINIMUM AND 49.0 ROCKWELL C MAXIMUM OVERALL |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | HEXAGON |
| Thread Direction | RIGHT-HAND |
| Width Between Flats | 0.553 INCHES MINIMUM AND 0.564 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM OVERALL |
| Thread Class | 3A A |
| Test Data Document | 81349-MIL-I-6868 SPECIFICATION (INCLUDES ENGINEERING TYPE BULLETINS, BROCHURES,ETC., THAT REFLECT SPECIFICATION TYPE DATA IN SPECIFICATION FORMAT; EXCLUDES COMMERCIAL CATALOGS, INDUSTRY DIRECTORIES, AND SIMILAR TRADE PUBLICATIONS, REFLECTING GENERAL TYPE DATA ON CERTAIN ENVIRONMENTAL AND PERFORMANCE REQUIREMENTS AND TEST CONDITIONS THAT ARE SHOWN AS "TYPICAL", "AVERAGE", "NOMINAL", ETC.). |
| Thread Quantity Per Inch | 28 |
| Material | STEEL COMP D6AC OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| 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 |
|---|---|
| A51B21645-11 PRIMARY | Northrop Grumman Systems Corporation (USA) |
| Reference | Meaning |
|---|---|
| A51B21645-11 | 3/9 Design control — primary reference Northrop Grumman Systems Corporation |
| A51B21645-11 | 5/9 Secondary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems |
NSN 5306-00-973-5594 is a Bolt,shoulder, manufactured by Northrop Grumman Systems Corporation, classified under FSC 5306, Bolts. Status: active.
NSN 5306-00-973-5594 has 1 manufacturer part number on file: A51B21645-11 (Northrop Grumman Systems Corporation).
Key specifications for A51B21645-11: Head Height: 0.210 INCHES NOMINAL IN; Fastener Length: 1.289 INCHES NOMINAL IN; Shoulder Length: 0.874 INCHES MINIMUM AND 0.884 INCHES MAXIMUM FIRST SHOULDER IN; Surface Treatment Document and Classification: MIL-C-8837,TY 2 CL 1 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL. 18 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.