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When your motion-control build demands consistent tooth engagement and reliable torque transfer, undersized or poorly machined gears become the weakest link. Engineers, makers, and automation integrators who need a dependable 1.5 Mod 45# steel spur gear across a wide tooth-count range will find this series covers the most common drive configurations in a single listing.
Each gear is machined from 45# medium-carbon steel, offering a balance of machinability and surface hardness suitable for moderate-load drive trains. The module is 1.5 (metric), with tooth counts spanning 12T to 35T and bore diameters from 6 mm (0.24 in) to 20 mm (0.79 in). Keyway variants (4 mm or 5 mm or 6 mm keyway) are available for shaft-locking applications. Overall gear width is typically 10–15 mm depending on tooth count; outer diameter scales with tooth count per standard module formula (OD = (T + 2) × Module).
Typical use cases include stepper motor pinion drives in 3D printers and laser cutters, rack-and-pinion linear actuators for CNC router axes, and small gearbox reduction stages in robotics joints and conveyor indexers — all applications where a compact 1.5 mod spur gear with a precise bore fit is critical to system accuracy.
Machined from 45# carbon steel for a practical balance of strength, wear resistance, and ease of secondary machining such as keyway broaching or bore enlargement.
A single consistent module across all variants ensures any two gears in this series mesh correctly, simplifying multi-stage gearbox design and spare-parts management.
Plain bore variants (6, 8, 10, 12, 14, 15, 16 mm) and keyway variants (12 mm + 4 mm key through 20 mm + 6 mm key) cover the majority of stepper, servo, and gearbox shaft standards.
Order a single gear for prototyping, a pair for a drive-and-idler setup, or a pack of five for production runs — all at consistent per-unit pricing.
Tooth profile and bore tolerances are suited for direct mounting on NEMA 17 and NEMA 23 stepper shafts, making these gears a drop-in choice for 3D printer extruder drives, laser cutter axes, and CNC router Z-columns.
Use as a pinion against a 1.5M rack for linear motion, or as a stage in a compound reduction gearbox. The standardized module ensures interchangeability with other 1.5M components across your build.
| Module | 1.5M (metric) |
|---|---|
| Tooth Count Range | 12T – 35T |
| Material | 45# Medium-Carbon Steel |
| Bore Diameter Options | 6 / 8 / 10 / 12 / 14 / 15 / 16 / 17 / 18 / 20 mm |
| Keyway Options | 4 mm (for 12 mm bore) / 5 mm (for 14–16 mm bore) / 6 mm (for 18–20 mm bore) |
| Pressure Angle | 20° (standard) |
| Gear Face Width | See variant options |
| Outer Diameter | (T + 2) × 1.5 mm — varies by tooth count |
| Surface Finish | See variant options |
| Pack Quantity | 1 / 2 / 5 pcs (select above) |
The tooth count determines the gear ratio and the pitch circle diameter. For a stepper motor pinion driving a rack, smaller tooth counts (12T–16T) give finer linear resolution per motor step. For gearbox reduction stages, pair a small pinion (e.g., 12T) with a larger gear (e.g., 36T or 48T of the same module) to achieve your target ratio. Use the formula: Ratio = Driven Teeth ÷ Driver Teeth.
Standard NEMA 17 stepper motors have a 5 mm output shaft. The closest plain bore in this series is 6 mm — you would need to use a set screw or locking collar, or select a 5 mm bore gear from a compatible series. For NEMA 23 motors with an 8 mm shaft, select the 8 mm bore variant directly.
Keyway variants are recommended when transmitting higher torque or when the gear must not slip under reversing loads. Select the keyway bore that matches your shaft: 12 mm bore uses a 4 mm key (DIN 6885 standard), 14–16 mm bores use a 5 mm key, and 18–20 mm bores use a 6 mm key. For light-duty or prototype applications, a plain bore with a set screw is often sufficient.
Yes. All gears in this listing share a 1.5M module and a standard 20° pressure angle, which means they are fully interchangeable and will mesh correctly with any other 1.5M spur gear, pinion, or rack of the same module and pressure angle, regardless of tooth count.
45# carbon steel provides moderate tensile strength (typically 600–800 MPa depending on heat treatment). For light-to-medium duty CNC and robotics applications at low-to-moderate speeds, these gears are well suited. For high-speed or heavy-load industrial gearboxes, consider hardened or alloy steel alternatives. If you need specific load ratings for your application, contact us to confirm.
45# carbon steel is not inherently corrosion resistant. For outdoor or humid environments, apply a light machine oil or grease coating, or consider a surface treatment such as black oxide or zinc plating after purchase. For fully corrosion-resistant applications, stainless steel or plastic gears of the same module would be more appropriate.
The available models and bore sizes are listed in the variant selectors above. If you require a tooth count or bore diameter outside the listed options, please contact us via the store's contact page — we may be able to source or recommend a suitable alternative within the 1.5M series.
