The Washer,flat, cataloged under National Stock Number 5310-00-641-6641, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Northrop Grumman Systems Corporation. Government technical data includes 10 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. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-00-641-6641 |
| Primary Part Number | SP4300-185 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Overall Diameter | 0.562 INCHES NOMINAL IN |
| Hardness Rating | 55.0 SHORE DUROMETER A MINIMUM AND 65.0 SHORE DUROMETER A MAXIMUM |
| Material Document and Classification | MIL-S-6855,CL 2,GR 60 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Cross-Sectional Shape Style | RECTANGULAR |
| Minimum Tensile Strength | 1500 POUNDS PER SQUARE INCH LBS |
| Peripheral Shape Style | ROUND |
| Material | RUBBER SYNTHETIC OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.250 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 |
|---|---|
| SP4300-185 PRIMARY | Northrop Grumman Systems Corporation (USA) |
NSN 5310-00-641-6641 is a Washer,flat, manufactured by Northrop Grumman Systems Corporation, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-641-6641 has 1 manufacturer part number on file: SP4300-185 (Northrop Grumman Systems Corporation).
Key specifications for SP4300-185: Overall Diameter: 0.562 INCHES NOMINAL IN; Hardness Rating: 55.0 SHORE DUROMETER A MINIMUM AND 65.0 SHORE DUROMETER A MAXIMUM; Material Document and Classification: MIL-S-6855,CL 2,GR 60 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL; Cross-Sectional Shape Style: RECTANGULAR. 10 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.