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When a standard spur gear introduces too much noise or axial play into your drive train, engineers and makers turn to helical gears for smoother, quieter power transfer. These stepped-bore helical gears are designed for builders working on CNC routers, robotic arms, conveyor drives, and custom motor transmission assemblies who need a reliable, drop-in gear with a defined bore and a consistent helix angle.
Each gear is machined from 45# carbon steel and features a 45° right-hand spiral angle with an integrated step (shoulder) on the bore side for precise axial positioning. Available in three modulus values — 1, 1.5, and 2 — with tooth counts ranging from 10 to 60 teeth and bore diameters from 8 mm (0.31 in) to 19 mm (0.75 in). Outer diameter scales with modulus and tooth count, typically ranging from approximately 12 mm (0.47 in) for the smallest variants up to 122 mm (4.80 in) for the largest.
Typical use cases include pairing with a matching left-spiral helical gear for parallel-shaft gearboxes in desktop CNC machines, integrating into stepper or servo motor output shafts for 3D printer extruder drives, and building custom reduction stages for robotic joint actuators where low backlash and quiet operation are critical.
Available in Modulus 1, 1.5, and 2 to match a wide range of gear ratio and torque requirements across different drive applications.
The 45° spiral angle delivers smooth, progressive tooth engagement that reduces vibration and noise compared to straight-cut spur gears in the same application.
The integrated shoulder step on the bore allows precise axial positioning on the shaft, eliminating the need for additional spacers in most installations.
Choose from 10 to 60 teeth and bore sizes from 8 mm to 19 mm, giving you the flexibility to match your exact shaft diameter and gear ratio target.
Machined from 45# medium-carbon steel for a balance of strength, machinability, and wear resistance suitable for continuous-duty motor transmission use.
Conforms to the standard 20° pressure angle, ensuring compatibility with off-the-shelf mating helical gears and standard gear-cutting tooling for custom modifications.
| Modulus Options | 1 / 1.5 / 2 |
|---|---|
| Helix Angle | 45° Right-Hand Spiral |
| Pressure Angle | 20° |
| Teeth Range | 10 – 60 Teeth (see variant options) |
| Bore Diameter | 8 / 10 / 12 / 14 / 15 / 17 / 19 mm (see variant options) |
| Bore Style | Stepped (shouldered) bore |
| Material | 45# Carbon Steel |
| Outer Diameter | See variant options |
| Face Width | See variant options |
| Quantity per Order | 1 PCS |
| Finish | Natural / uncoated machined surface |
Modulus determines the size of the gear teeth relative to the pitch diameter. A higher modulus (e.g., 2) means larger, stronger teeth suitable for higher torque loads, while a lower modulus (e.g., 1) gives finer teeth for compact, lower-torque drives. Match the modulus to your mating gear and confirm the center distance fits your housing before ordering.
Measure your motor or gearbox output shaft diameter with a caliper. Select the bore option that matches — available in 8, 10, 12, 14, 15, 17, and 19 mm. The stepped bore provides a shoulder for axial location; you can secure the gear with a set screw or retaining ring in the groove behind the step.
No. Helical gears must mesh with other helical gears of the same modulus, pressure angle, and opposite hand (a right-hand gear meshes with a left-hand gear on parallel shafts). Mixing helical and spur gears of the same modulus is not recommended as the tooth geometry differs and will cause rapid wear.
45# carbon steel offers good mechanical strength but has limited corrosion resistance in wet or outdoor environments. For applications exposed to moisture, consider applying a light machine oil coating for protection, or consult us about alternative material options. For dry, enclosed gearbox environments this material performs reliably over extended service life.
Gear ratio equals the number of teeth on the driven gear divided by the number of teeth on the driving gear. For example, pairing a 15-tooth driver with a 30-tooth driven gear gives a 2:1 reduction. Select your tooth counts based on your required ratio and verify the resulting center distance fits your mechanical design.
A 45° helix angle maximizes the overlap ratio, meaning multiple teeth are always in contact simultaneously. This results in very smooth, quiet operation and distributes load across more tooth surface area. The trade-off is a higher axial thrust force on the shaft bearings, so ensure your bearing selection accounts for both radial and axial loads.
Yes. These gears are well-suited for desktop CNC router spindle drives, extruder gear trains, and Z-axis reduction stages where quiet operation and compact size matter. Select the modulus and tooth count that matches your target gear ratio and confirm the bore fits your stepper or servo motor shaft diameter.
