The Nut,plain,square, cataloged under National Stock Number 5310-00-187-4261, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. Government technical data includes 11 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government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 | 5310-00-187-4261 |
| Item Name | Nut,plain,square |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Status | ACTIVE |
| Width Across Flats | 0.438 INCHES NOMINAL IN |
| Thread Series | UNIFIED NATIONAL COARSE (UNC) |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 0.250 INCHES IN |
| Nut Height | 0.188 INCHES NOMINAL IN |
| Surface Treatment | CHROMATE ZINC OVERALL |
| Nut Style | SQUARE |
| Thread Class | 2B |
| Thread Quantity Per Inch | 20 |
| Material | STEEL OVERALL |
| Bearing Surface Type | FLAT |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| 106204 | 5/9 Secondary reference At and T Corp |
| 106204 | C/1 Advisory reference — outside the item-of-supply concept Lucent Technologies Inc Corporate Headquarters |
| 106204 | 3/9 Design control — primary reference American Telephone and Telegraph Co |
NSN 5310-00-187-4261 is a Nut,plain,square, classified under FSC 5310, Nuts and Washers. Status: active.
3 possible matches (shared part number, not a government interchangeability claim): 4920-00-686-1615, 4220-00-910-6031, 7930-01-418-1507. Verify interchangeability with system specifications before substitution.
Key specifications for 5310-00-187-4261: Width Across Flats: 0.438 INCHES NOMINAL IN; Thread Series: UNIFIED NATIONAL COARSE (UNC); Thread Direction: RIGHT-HAND; Nominal Thread Size: 0.250 INCHES IN. 11 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.