The Nut,plain,clinch, cataloged under National Stock Number 5310-00-031-0661, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Penn Engineering & Manufacturing Corp. Government technical data includes 13 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-00-031-0661 |
| Primary Part Number | S256-2 |
| Item Name | Nut,plain,clinch |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Penn Engineering & Manufacturing Corp |
| Status | ACTIVE |
| Surface Treatment Document and Classification | QQ-P-416,TY 1,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Series | UNIFIED NATIONAL COARSE (UNC) |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 0.086 INCHES IN |
| Nut Diameter | 0.250 INCHES NOMINAL IN |
| Pilot Diameter | 0.164 INCHES MAXIMUM IN |
| Pilot Length | 0.054 INCHES MAXIMUM IN |
| Nut Height | 0.124 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM OVERALL |
| Nut Style | CLINCH |
| Thread Class | 2B |
| Thread Quantity Per Inch | 56 |
| Material | STEEL OVERALL |
| 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 |
|---|---|
| S256-2 PRIMARY | Penn Engineering & Manufacturing Corp (USA) |
| Reference | Meaning |
|---|---|
| S-256-2CI | 5/9 Secondary reference Penn Engineering & Manufacturing Corp |
NSN 5310-00-031-0661 is a Nut,plain,clinch, manufactured by Penn Engineering & Manufacturing Corp, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-031-0661 has 1 manufacturer part number on file: S256-2 (Penn Engineering & Manufacturing Corp).
1 possible match (shared part number, not a government interchangeability claim): 5910-00-112-7000. Verify interchangeability with system specifications before substitution.
Key specifications for S256-2: Surface Treatment Document and Classification: QQ-P-416,TY 1,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL; Thread Series: UNIFIED NATIONAL COARSE (UNC); Thread Direction: RIGHT-HAND; Nominal Thread Size: 0.086 INCHES IN. 13 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.