The Nut,self-Locking,castellated,dou, cataloged under National Stock Number 5310-01-064-6566, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Sps Technologies, Llc Dba PB Fasteners. Government technical data includes 15 specifications, cited from the U.S. Government catalog. The record lists 3 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-01-064-6566 |
| Primary Part Number | 78238-524 |
| Item Name | Nut,self-Locking,castellated,dou |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Sps Technologies, Llc Dba PB Fasteners |
| Status | ACTIVE |
| Width Across Flats | 0.492 INCHES MINIMUM AND 0.502 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | MIL-C-8837,TY II,CL 2 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Series | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Thread Pitch in Millimeters | 1.058 |
| Hardness Rating | 40.0 ROCKWELL C MINIMUM AND 44.0 ROCKWELL C MAXIMUM |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 0.312 INCHES IN |
| Locking Feature | PREVAILING TORQUE ALL METAL DESIGN |
| Nut Height | 0.276 INCHES NOMINAL IN |
| Surface Treatment | CADMIUM OVERALL |
| Nut Style | CASTELLATED, DOUBLE HEXAGON |
| Thread Class | 3B |
| Thread Quantity Per Inch | 24 |
| Material | STEEL COMP H11 OVERALL |
| Bearing Surface Type | CHAMFERED |
| 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 |
|---|---|
| 78238-524 PRIMARY | Sps Technologies, Llc Dba PB Fasteners (USA) |
| ST3M749-5 | Howmet Global Fastening Systems Inc (USA) |
| HS2370-5 | Satair A/s (DNK) |
| Reference | Meaning |
|---|---|
| HS2370-5 | 5/9 Secondary reference Howmet Global Fastening Systems Inc |
| VN3000AB054 | 5/2 Secondary reference U.S. Government activity |
| ST3M749-5 | 5/9 Secondary reference The Boeing Company Div Defense |
NSN 5310-01-064-6566 is a Nut,self-Locking,castellated,dou, manufactured by Sps Technologies, Llc Dba PB Fasteners, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-064-6566 has 3 manufacturer part numbers on file: 78238-524 (Sps Technologies, Llc Dba PB Fasteners), ST3M749-5 (Howmet Global Fastening Systems Inc), HS2370-5 (Satair A/s).
Key specifications for 78238-524: Width Across Flats: 0.492 INCHES MINIMUM AND 0.502 INCHES MAXIMUM IN; Surface Treatment Document and Classification: MIL-C-8837,TY II,CL 2 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL; Thread Series: UNIFIED NATIONAL JOINT FINE (UNJF); Thread Pitch in Millimeters: 1.058. 15 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.