The Seat,valve, cataloged under National Stock Number 4820-01-178-8686, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. Government technical data includes 13 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-178-8686 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Status | ACTIVE |
| Thread Length | 1.000 INCHES NOMINAL SINGLE THREADED PORTION IN |
| Criticality Code Justification | ZZZY |
| Style Designator | PLAIN THREADED |
| Material Document and Classification | QQ-N-281 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Body Inside Diameter | 0.750 INCHES NOMINAL IN |
| Nominal Thread Size | 1.125 INCHES SINGLE THREADED PORTION IN |
| Thread Class | 3A SINGLE THREADED PORTION A |
| Thread Quantity Per Inch | 18 SINGLE THREADED PORTION |
| Material | NICKEL ALLOY OVERALL |
| Seat Angle in Deg | 45.000 NOMINAL |
| Thread Series Designator | UNEF SINGLE THREADED PORTION |
| Reference Number Differentiating Characteristics | MATERIAL WILL BE IN ACCORDANCE WITH SHIPS PARTS CONTROL CENTER ACTIVITY HX QUALITY CONTROL,MANUFACTURING AND TESTING SPECIFICATIONS |
| Seating Surface Shape | ANGULAR |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL F — Mutilate — Cut |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | C |
| Reference | Meaning |
|---|---|
| 20212FIND5 | 5/1 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| 8731 PIECE 4 | 5/1 Secondary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
| A7440.002.128SPCLN | 3/1 Design control — primary reference Anderson Greenwood Lp Dba Anderson Greenwood Crosby |
NSN 4820-01-178-8686 is a Seat,valve, classified under FSC 4820, Valves, Nonpowered. Status: active.
Key specifications for 4820-01-178-8686: Overall Height: 1.250 INCHES NOMINAL IN; Thread Length: 1.000 INCHES NOMINAL SINGLE THREADED PORTION IN; Criticality Code Justification: ZZZY; Style Designator: PLAIN THREADED. 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.
NSN 4820-01-178-8686 has DEMIL Code F. Demilitarization may be required before disposal or transfer to non-military entities.
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.