The Washer,flat, cataloged under National Stock Number 5310-00-004-0401, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp. Government technical data includes 9 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 | 5310-00-004-0401 |
| Primary Part Number | SS5072S4 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp |
| Status | ACTIVE |
| Surface Treatment Document and Classification | MIL-C-5541 MIL SPEC 1ST TREATMENT RESPONSE AND MIL-A-8625 MIL SPEC 2ND TREATMENT RESPONSE OVERALL |
| Overall Diameter | 0.370 INCHES MINIMUM AND 0.395 INCHES MAXIMUM IN |
| Heat Treatment | T-3 SOLUTION HEAT TREATED, COLD WORKED |
| Cross-Sectional Shape Style | RECTANGULAR |
| Surface Treatment | OXIDE FILM AND ANODIZE OVERALL |
| Peripheral Shape Style | ROUND |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.136 INCHES MINIMUM AND 0.141 INCHES MAXIMUM IN |
| Thickness | 0.016 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 |
|---|---|
| SS5072S4 PRIMARY | Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp (USA) |
NSN 5310-00-004-0401 is a Washer,flat, manufactured by Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-004-0401 has 1 manufacturer part number on file: SS5072S4 (Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp).
Key specifications for SS5072S4: Surface Treatment Document and Classification: MIL-C-5541 MIL SPEC 1ST TREATMENT RESPONSE AND MIL-A-8625 MIL SPEC 2ND TREATMENT RESPONSE OVERALL; Overall Diameter: 0.370 INCHES MINIMUM AND 0.395 INCHES MAXIMUM IN; Heat Treatment: T-3 SOLUTION HEAT TREATED, COLD WORKED; Cross-Sectional Shape Style: RECTANGULAR. 9 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.