The Washer,flat, cataloged under National Stock Number 5310-01-009-5620, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Sargent Aerospace & Defense, Llc Dba Sargent Controls & Aerospace Div Sargent Controls & Aerospace. Government technical data includes 5 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 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 | 5310-01-009-5620 |
| Primary Part Number | B-781 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Sargent Aerospace & Defense, Llc Dba Sargent Controls & Aerospace Div Sargent Controls & Aerospace |
| Status | ACTIVE |
| Overall Diameter | 0.620 INCHES NOMINAL IN |
| Material Document and Classification | QQ-S-685 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Material | STEEL COMP 4130 OVERALL |
| Hole Diameter | 0.265 INCHES NOMINAL IN |
| Thickness | 0.031 INCHES NOMINAL 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 |
|---|---|
| B-781 PRIMARY | Sargent Aerospace & Defense, Llc Dba Sargent Controls & Aerospace Div Sargent Controls & Aerospace (USA) |
NSN 5310-01-009-5620 is a Washer,flat, manufactured by Sargent Aerospace & Defense, Llc Dba Sargent Controls & Aerospace Div Sargent Controls & Aerospace, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-009-5620 has 1 manufacturer part number on file: B-781 (Sargent Aerospace & Defense, Llc Dba Sargent Controls & Aerospace Div Sargent Controls & Aerospace).
1 possible match (shared part number, not a government interchangeability claim): 7010-01-505-5346. Verify interchangeability with system specifications before substitution.
Key specifications for B-781: Overall Diameter: 0.620 INCHES NOMINAL IN; Material Document and Classification: QQ-S-685 FED SPEC SINGLE MATERIAL RESPONSE OVERALL; End Item Identification: KC-135 STRATOLIFTER AIRCRAFT; Material: STEEL COMP 4130 OVERALL. 5 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.