The Washer,flat, cataloged under National Stock Number 5310-01-577-5628, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Mcmaster-Carr Supply Company. Government technical data includes 7 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 5310-01-577-5628 |
| Primary Part Number | 91860A033 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Mcmaster-Carr Supply Company |
| Status | ACTIVE |
| Overall Diameter | 1.375 INCHES NOMINAL IN |
| Cross-Sectional Shape Style | RECTANGULAR |
| Peripheral Shape Style | ROUND |
| Material | STEEL CORROSION RESISTING OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.563 INCHES NOMINAL IN |
| Thickness | 0.073 INCHES MINIMUM AND 0.083 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 |
|---|---|
| 91860A033 | Mcmaster-Carr Supply Company (USA) |
| Reference | Meaning |
|---|---|
| 6301E06-ITEM21 | 3/2 Design control — primary reference U.S. Government activity |
NSN 5310-01-577-5628 is a Washer,flat, manufactured by Mcmaster-Carr Supply Company, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-577-5628 has 1 manufacturer part number on file: 91860A033 (Mcmaster-Carr Supply Company).
1 possible match (shared part number, not a government interchangeability claim): 5310-01-588-5054. Verify interchangeability with system specifications before substitution.
Key specifications for 91860A033: Overall Diameter: 1.375 INCHES NOMINAL IN; Cross-Sectional Shape Style: RECTANGULAR; Peripheral Shape Style: ROUND; Material: STEEL CORROSION RESISTING OVERALL. 7 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.