The Seat,helical Compression Spring, cataloged under National Stock Number 5340-01-129-8518, is classified within Federal Supply Class 5340 (Hardware, Commercial) of the Hardware and Abrasives group. Government technical data includes 14 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active. Unit of issue: EA.
| Parameter | Value |
|---|---|
| NSN | 5340-01-129-8518 |
| Item Name | Seat,helical Compression Spring |
| FSC / FSG | 5340 / 53 — Hardware, Commercial |
| Status | ACTIVE |
| First Step Diameter | 0.3280 INCHES NOMINAL IN |
| Material Hardness Rating | 57.0 ROCKWELL C MINIMUM AND 60.0 ROCKWELL C MAXIMUM |
| End Diameter | 0.3280 INCHES NOMINAL IN |
| Surface Treatment Document and Classification | PS13001, MCDONNELL DOUGLAS CORP MFR REF SINGLE TREATMENT RESPONSE |
| Second End Diameter | 0.2100 INCHES NOMINAL IN |
| Distance From End to First Step | 0.2520 INCHES NOMINAL IN |
| Design Type | SOLID |
| Style Designator | SEAT |
| Material Document and Classification | QQ-S-763, CLASS 440C FED SPEC SINGLE MATERIAL RESPONSE |
| First Step Length | 0.0600 INCHES NOMINAL IN |
| Surface Treatment | PASSIVATE |
| Spherical Seat Top Radius | 0.0630 INCHES NOMINAL IN |
| Bore Diameter | 0.1250 INCHES NOMINAL IN |
| Material | STEEL COMP 440C |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | Possible hazard — SDS may be required (DLA HMIC P) |
| Criticality Code | X |
| Unit of Issue | EA |
| Reference | Meaning |
|---|---|
| 36712 | 3/2 Design control — primary reference U.S. Government activity |
| 10112550 | 6/9 Informative reference only Nimikkeistokeskus Ncb Finland |
NSN 5340-01-129-8518 is a Seat,helical Compression Spring, classified under FSC 5340, Hardware, Commercial. Status: active.
Key specifications for 5340-01-129-8518: Overall Height: 0.4170 INCHES NOMINAL IN; First Step Diameter: 0.3280 INCHES NOMINAL IN; Material Hardness Rating: 57.0 ROCKWELL C MINIMUM AND 60.0 ROCKWELL C MAXIMUM; End Diameter: 0.3280 INCHES NOMINAL IN. 14 specifications are documented in the U.S. Government catalog.
Possible hazard — SDS may be required (DLA HMIC P). 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.