The Washer,recessed, cataloged under National Stock Number 5310-01-254-5420, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Lockheed Martin Corp Electronics and Missiles Div. Government technical data includes 11 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog.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 | 5310-01-254-5420 |
| Primary Part Number | 240840 |
| Item Name | Washer,recessed |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Lockheed Martin Corp Electronics and Missiles Div |
| Status | ACTIVE |
| Surface Treatment Document and Classification | QQ-P-35,TYPE 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Style Designator | RECESSED |
| Material Document and Classification | QQ-S-763,COND A FED SPEC ALL MATERIAL RESPONSES OVERALL |
| Outside Diameter | 0.531 INCHES NOMINAL IN |
| Recess Depth | 0.076 INCHES NOMINAL IN |
| Material Thickness | 0.100 INCHES NOMINAL IN |
| Recess Diameter | 0.404 INCHES MINIMUM AND 0.412 INCHES MAXIMUM IN |
| Surface Treatment | PASSIVATE OVERALL |
| Material | STEEL COMP 321 OR STEEL COMP 347 OVERALL |
| Hole Diameter | 0.252 INCHES MINIMUM AND 0.260 INCHES MAXIMUM IN |
| Recess Angle | 90.0 DEGREES NOMINAL |
| 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 |
|---|---|
| 240840 PRIMARY | Lockheed Martin Corp Electronics and Missiles Div (USA) |
| Reference | Meaning |
|---|---|
| 240840 | 5/9 Secondary reference Springfield Spring Corp the |
NSN 5310-01-254-5420 is a Washer,recessed, manufactured by Lockheed Martin Corp Electronics and Missiles Div, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-254-5420 has 1 manufacturer part number on file: 240840 (Lockheed Martin Corp Electronics and Missiles Div).
Key specifications for 240840: Surface Treatment Document and Classification: QQ-P-35,TYPE 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL; Style Designator: RECESSED; Material Document and Classification: QQ-S-763,COND A FED SPEC ALL MATERIAL RESPONSES OVERALL; Outside Diameter: 0.531 INCHES NOMINAL IN. 11 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.