The Gear,helical, cataloged under National Stock Number 3020-00-239-5498, 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 Siemens Energy, Inc.. Government technical data includes 18 specifications, cited from the U.S. Government catalog. The record lists 4 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 12 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 3020-00-239-5498 |
| Primary Part Number | G7798PC121 |
| Item Name | Gear,helical |
| FSC / FSG | 3020 / 30 — Gears, Pulleys, Sprockets, and Transmission Chain |
| Manufacturer | Siemens Energy, Inc. |
| Status | ACTIVE |
| Helix Angle | 44.4129 DEGREES |
| Hub Nominal Diameter | 1.250 INCHES FIRST END IN |
| Hub Nominal Diameter | 1.250 INCHES SECOND END IN |
| Teeth Quantity | 43 |
| Body Style | WEBBED, SOLID |
| Tooth Direction | RIGHT |
| Mounting Hole Type and Quantity | 1 THREADED TRANSVERSELY THROUGH HUB FIRST END |
| Nominal Distance Between Body Face and Protruding Hub End | 0.250 INCHES FIRST END IN |
| Teeth Type | SINGLE HELIX |
| Nominal Overall Length | 0.875 INCHES IN |
| Style Designator | ONE PROTRUDING HUB, ONE FLUSH HUB |
| Pitch Diameter | 3.2001 INCHES NOMINAL IN |
| Tooth Form | STANDARD |
| Nominal Outside Diameter | 3.3001 INCHES IN |
| Mounting Hole Thread Quantity Per Inch | 20 TRANSVERSELY THROUGH HUB FIRST END |
| Pressure Angle | 15.0000 DEGREES |
| Attachment Method | MOUNTING HOLE |
| Face Nominal Width | 0.625 INCHES IN |
| 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 |
|---|---|
| G7798PC121 PRIMARY | Siemens Energy, Inc. (USA) |
| G7803PC121 PRIMARY | Siemens Energy, Inc. (USA) |
| G7907PC121 PRIMARY | Siemens Energy, Inc. (USA) |
| G7902PC121 PRIMARY | Siemens Energy, Inc. (USA) |
| Reference | Meaning |
|---|---|
| G9981PC121 | 5/9 Secondary reference Imo Industries Inc Delroyd Worm Gear Div |
| G9981PC121 | 5/9 Secondary reference Siemens Energy, Inc. |
| G9981PC21 | 5/9 Secondary reference Siemens Energy, Inc. |
| W416CS1X5 | 5/9 Secondary reference Imo Industries Inc Delroyd Worm Gear Div |
| W416CS1X5 | 5/9 Secondary reference Siemens Energy, Inc. |
| G9981PC21 | 5/9 Secondary reference Imo Industries Inc Delroyd Worm Gear Div |
| G9759PC121 | 5/9 Secondary reference Imo Industries Inc Delroyd Worm Gear Div |
| G9759PC121 | 5/9 Secondary reference Siemens Energy, Inc. |
| G9986PC121 | 5/9 Secondary reference Siemens Energy, Inc. |
| G9986PC121 | 5/9 Secondary reference Imo Industries Inc Delroyd Worm Gear Div |
| G9754PC121 | 5/9 Secondary reference Imo Industries Inc Delroyd Worm Gear Div |
| G9754PC121 | 5/9 Secondary reference Siemens Energy, Inc. |
NSN 3020-00-239-5498 is a Gear,helical, manufactured by Siemens Energy, Inc., classified under FSC 3020, Gears, Pulleys, Sprockets, and Transmission Chain. Status: active.
NSN 3020-00-239-5498 has 4 manufacturer part numbers on file: G7798PC121 (Siemens Energy, Inc.), G7803PC121 (Siemens Energy, Inc.), G7907PC121 (Siemens Energy, Inc.), G7902PC121 (Siemens Energy, Inc.).
Key specifications for G7798PC121: Helix Angle: 44.4129 DEGREES; Hub Nominal Diameter: 1.250 INCHES FIRST END IN; Hub Nominal Diameter: 1.250 INCHES SECOND END IN; Teeth Quantity: 43. 18 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.