The Washer,concave, cataloged under National Stock Number 5310-00-975-2741, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Esna, Llc. Government technical data includes 12 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 5310-00-975-2741 |
| Primary Part Number | 4084-06 |
| Item Name | Washer,concave |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Esna, Llc |
| Status | ACTIVE |
| Surface Treatment Document and Classification | AMS 2417 ASSN STD 1ST TREATMENT RESPONSE AND AMS 2417 ASSN STD 2ND TREATMENT RESPONSE OVERALL |
| Radius | 0.385 INCHES MINIMUM AND 0.415 INCHES MAXIMUM IN |
| Hardness Rating | 41.0 ROCKWELL C MINIMUM AND 48.0 ROCKWELL C MAXIMUM |
| Style Designator | CONCAVE |
| Material Document and Classification | AMS 6304 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Outside Diameter | 0.640 INCHES MAXIMUM IN |
| Material Thickness | 0.105 INCHES MINIMUM AND 0.135 INCHES MAXIMUM IN |
| Specification/standard Data | 80205-NAS1288 PROFESSIONAL/INDUSTRIAL ASSOCIATION STANDARD |
| Recess Diameter | 0.620 INCHES MAXIMUM IN |
| Surface Treatment | NICKEL AND ZINC OVERALL |
| Material | STEEL OVERALL |
| Hole Diameter | 0.435 INCHES MINIMUM AND 0.445 INCHES MAXIMUM IN |
| 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 |
|---|---|
| 4084-06 | Esna, Llc (USA) |
| Reference | Meaning |
|---|---|
| NAS1288-6W | 3/2 Design control — primary reference U.S. Government activity |
| 4084-06 | 5/9 Secondary reference Harvard Industries Inc |
NSN 5310-00-975-2741 is a Washer,concave, manufactured by Esna, Llc, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-975-2741 has 1 manufacturer part number on file: 4084-06 (Esna, Llc).
1 possible match (shared part number, not a government interchangeability claim): 4720-01-681-0729. Verify interchangeability with system specifications before substitution.
Key specifications for 4084-06: Surface Treatment Document and Classification: AMS 2417 ASSN STD 1ST TREATMENT RESPONSE AND AMS 2417 ASSN STD 2ND TREATMENT RESPONSE OVERALL; Radius: 0.385 INCHES MINIMUM AND 0.415 INCHES MAXIMUM IN; Hardness Rating: 41.0 ROCKWELL C MINIMUM AND 48.0 ROCKWELL C MAXIMUM; Style Designator: CONCAVE. 12 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.