The Washer,flat, cataloged under National Stock Number 5310-01-159-6590, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Hiab Usa Inc. Government technical data includes 12 specifications, cited from the U.S. Government catalog. The record lists 2 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 5310-01-159-6590 |
| Primary Part Number | 991 4111 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Hiab Usa Inc |
| Status | ACTIVE |
| Overall Diameter | 22.0 MILLIMETERS NOMINAL MM |
| Heat Treatment | QUENCHED AND TEMPERED |
| Hardness Rating | 225.0 BRINELL STANDARD MINIMUM AND 300.0 BRINELL STANDARD MAXIMUM |
| Material Document and Classification | 8.8,FSCM 21969 MFR REF SINGLE MATERIAL RESPONSE OVERALL |
| Cross-Sectional Shape Style | RECTANGULAR |
| Surface Treatment | ZINC OVERALL |
| Minimum Tensile Strength | 113783 POUNDS PER SQUARE INCH LBS |
| Peripheral Shape Style | ROUND |
| Material | STEEL OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 10.5 MILLIMETERS NOMINAL MM |
| Thickness | 2.0 MILLIMETERS NOMINAL MM |
| 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 |
|---|---|
| 4HC41 | Oshkosh Defense Llc (USA) |
| 991 4111 PRIMARY | Hiab Usa Inc (USA) |
| Reference | Meaning |
|---|---|
| 6V8495 | C/1 Advisory reference — outside the item-of-supply concept Caterpillar Inc Div Caterpillar Defense |
| 760 598 | C/1 Advisory reference — outside the item-of-supply concept Elme North America Inc |
| 4HC41 | 5/9 Secondary reference Oshkosh Corp |
NSN 5310-01-159-6590 is a Washer,flat, manufactured by Hiab Usa Inc, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-159-6590 has 2 manufacturer part numbers on file: 4HC41 (Oshkosh Defense Llc), 991 4111 (Hiab Usa Inc).
1 possible match (shared part number, not a government interchangeability claim): 3020-01-163-4970. Verify interchangeability with system specifications before substitution.
Key specifications for 991 4111: Overall Diameter: 22.0 MILLIMETERS NOMINAL MM; Heat Treatment: QUENCHED AND TEMPERED; Hardness Rating: 225.0 BRINELL STANDARD MINIMUM AND 300.0 BRINELL STANDARD MAXIMUM; Material Document and Classification: 8.8,FSCM 21969 MFR REF SINGLE MATERIAL RESPONSE OVERALL. 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.