The Gear Cluster, cataloged under National Stock Number 3020-01-178-5851, is classified within Federal Supply Class 3020 (Gears, Pulleys, Sprockets, and Transmission Chain) of the Mechanical Power Transmission Equipment group. Government technical data includes 14 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 3020-01-178-5851 |
| Item Name | Gear Cluster |
| FSC / FSG | 3020 / 30 — Gears, Pulleys, Sprockets, and Transmission Chain |
| Status | ACTIVE |
| Design Type | SPUR SECOND GEAR |
| Design Type | SPUR FIRST GEAR |
| Bore Style | PLAIN BOTH ENDS |
| Hardness Rating | 35.0 ROCKWELL A MINIMUM AND 45.0 ROCKWELL A MAXIMUM OVERALL |
| Nominal Overall Length | 4.547 INCHES IN |
| Material Document and Classification | AMS 6260 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Hub Style Designator | 1 STEP FIRST END |
| Hub Style Designator | 1 GROOVE SECOND END |
| Hub Nominal Length | 1.531 INCHES FIRST END IN |
| Hub Nominal Length | 0.444 INCHES BETWEEN FIRST AND SECOND GEAR IN |
| Nominal Outside Diameter | 1.6000 INCHES FIRST GEAR IN |
| Nominal Outside Diameter | 3.9380 INCHES SECOND GEAR IN |
| Material | STEEL COMP E9310 OVERALL |
| Construction | SOLID |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL Q — CCL Item — Commerce Control List |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| 709682 | 3/2 Design control — primary reference U.S. Government activity |
NSN 3020-01-178-5851 is a Gear Cluster, classified under FSC 3020, Gears, Pulleys, Sprockets, and Transmission Chain. Status: active.
1 possible match (shared part number, not a government interchangeability claim): 1730-01-391-9905. Verify interchangeability with system specifications before substitution.
Key specifications for 3020-01-178-5851: Design Type: SPUR SECOND GEAR; Design Type: SPUR FIRST GEAR; Bore Style: PLAIN BOTH ENDS; Hardness Rating: 35.0 ROCKWELL A MINIMUM AND 45.0 ROCKWELL A MAXIMUM OVERALL. 14 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 3020-01-178-5851 has DEMIL Code Q. 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.