The Nut,self-Locking,hexagon, cataloged under National Stock Number 5310-00-166-1403, 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-00-166-1403 |
| Primary Part Number | 43781 |
| Item Name | Nut,self-Locking,hexagon |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Sps Technologies, Llc Dba PB Fasteners |
| Status | ACTIVE |
| Width Across Flats | 0.616 INCHES MINIMUM AND 0.627 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | AMS 2400 ASSN STD SINGLE TREATMENT RESPONSE OVERALL EXCEPT INSERT |
| Thread Series | UNF |
| Material Document and Classification | AMS 5024 ASSN STD SINGLE MATERIAL RESPONSE NUT |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 0.438 INCHES IN |
| Locking Feature | PREVAILING TORQUE WITH NONMETALLIC INSERT |
| Nut Height | 0.438 INCHES MINIMUM AND 0.468 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM AND CHROMATE OVERALL EXCEPT INSERT |
| Nut Style | HEXAGON |
| Thread Class | 3B |
| Thread Quantity Per Inch | 20 |
| Material | PLASTIC POLYAMIDE NYLON LOCKING INSERT |
| Material | STEEL COMP 1137 NUT |
| 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 |
NSN 5310-00-166-1403 is a Nut,self-Locking,hexagon, manufactured by Sps Technologies, Llc Dba PB Fasteners, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-166-1403 has 3 manufacturer part numbers on file: 43781 (Sps Technologies, Llc Dba PB Fasteners), 43781 (Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney), 43781 (Esna, Llc).
3 possible matches (shared part number, not a government interchangeability claim): 5985-01-333-8944, 5120-01-398-7643, 6680-01-494-7534. Verify interchangeability with system specifications before substitution.
Key specifications for 43781: Width Across Flats: 0.616 INCHES MINIMUM AND 0.627 INCHES MAXIMUM IN; Surface Treatment Document and Classification: AMS 2400 ASSN STD SINGLE TREATMENT RESPONSE OVERALL EXCEPT INSERT; Thread Series: UNF; Material Document and Classification: AMS 5024 ASSN STD SINGLE MATERIAL RESPONSE NUT. 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.