The Washer,flat, cataloged under National Stock Number 5310-00-855-7257, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney. Government technical data includes 13 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-00-855-7257 |
| Primary Part Number | 431878 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney |
| Status | ACTIVE |
| Surface Finish | 63.0 MICROINCHES BOTTOM |
| Surface Finish | 90.0 MICROINCHES OUTER |
| Surface Finish | 63.0 MICROINCHES INNER |
| Surface Finish | 63.0 MICROINCHES TOP |
| Overall Diameter | 0.375 INCHES NOMINAL IN |
| Material Document and Classification | AMS 5505 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Cross-Sectional Shape Style | RECTANGULAR |
| Surface Treatment | PASSIVATE OVERALL |
| Peripheral Shape Style | ROUND |
| Material | STEEL COMP 410 OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.097 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 |
|---|---|
| 431878 PRIMARY | Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney (USA) |
| Reference | Meaning |
|---|---|
| 431878 | 5/9 Secondary reference Turbo Power & Marine System Inc Sub of United Technologies Corp |
NSN 5310-00-855-7257 is a Washer,flat, manufactured by Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-855-7257 has 1 manufacturer part number on file: 431878 (Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney).
Key specifications for 431878: Surface Finish: 63.0 MICROINCHES BOTTOM; Surface Finish: 90.0 MICROINCHES OUTER; Surface Finish: 63.0 MICROINCHES INNER; Surface Finish: 63.0 MICROINCHES TOP. 13 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.