The Gear,spur, cataloged under National Stock Number 3020-01-256-3690, is classified within Federal Supply Class 3020 (Gears, Pulleys, Sprockets, and Transmission Chain) of the Mechanical Power Transmission Equipment group. The manufacturer of record is Dynalec Corporation. Government technical data includes 12 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 3020-01-256-3690 |
| Primary Part Number | MB4202-1 PIECE 19, 20 |
| Item Name | Gear,spur |
| FSC / FSG | 3020 / 30 — Gears, Pulleys, Sprockets, and Transmission Chain |
| Manufacturer | Dynalec Corporation |
| Status | ACTIVE |
| Bore Nominal Diameter | 0.500 INCHES BOTH ENDS IN |
| Teeth Quantity | 135 |
| Bore Style | PLAIN BOTH ENDS |
| Style Designator | PROTRUDING HUB |
| Material Document and Classification | QQ-A-267 FED SPEC SINGLE MATERIAL RESPONSE HUB |
| Material Document and Classification | QQ-A-355 FED SPEC SINGLE MATERIAL RESPONSE BODY |
| Pitch Diameter | 2.8125 INCHES NOMINAL IN |
| Tooth Form | STANDARD |
| Hub Style Designator | PLAIN FIRST END |
| Nominal Outside Diameter | 2.854 INCHES IN |
| Pressure Angle | 14.5000 DEGREES |
| Material | ALUMINUM ALLOY 2024 OVERALL |
| 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 |
|---|---|
| MB4202-1 PIECE 19, 20 PRIMARY | Dynalec Corporation (USA) |
| 4L79 PRIMARY | Dynalec Corporation (USA) |
| Reference | Meaning |
|---|---|
| 4L79 | 5/9 Secondary reference The Electric Tachometer Corp. |
| MB4202-1 | D/9 Drawing number reference only The Electric Tachometer Corp. |
| MB4202-1 PIECE 19,20 | 5/9 Secondary reference The Electric Tachometer Corp. |
NSN 3020-01-256-3690 is a Gear,spur, manufactured by Dynalec Corporation, classified under FSC 3020, Gears, Pulleys, Sprockets, and Transmission Chain. Status: active.
NSN 3020-01-256-3690 has 2 manufacturer part numbers on file: MB4202-1 PIECE 19, 20 (Dynalec Corporation), 4L79 (Dynalec Corporation).
2 possible matches (shared part number, not a government interchangeability claim): 6320-01-267-7990, 6320-01-364-1732. Verify interchangeability with system specifications before substitution.
Key specifications for MB4202-1 PIECE 19, 20: Bore Nominal Diameter: 0.500 INCHES BOTH ENDS IN; Teeth Quantity: 135; Bore Style: PLAIN BOTH ENDS; Style Designator: PROTRUDING HUB. 12 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.