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When spur gears generate too much noise or vibration for your application, engineers and makers turn to helical gears for smoother, quieter power transfer. These 45° helical gears are designed for builders working on CNC routers, robotic joints, motorized actuators, and custom drive trains who need reliable torque transmission without the chatter of straight-cut teeth.
Each gear is machined from carbon steel with a stepped bore hub, available in Modulus 1, 1.5, 2, and 3. Tooth counts range from 10 to 60 teeth, and bore diameters span 8 mm (0.31 in) to 20 mm (0.79 in). The 45° helix angle is available in both left-hand and right-hand spiral orientations to suit paired-gear assemblies.
Typical use cases include CNC axis drives requiring low-backlash helical gear sets, robotic arm joint reduction stages using paired left/right spiral gears, and custom motor transmission gearboxes for 3D printers, automation rigs, and DIY electric vehicles.
| Modulus Options | 1 / 1.5 / 2 / 3 |
|---|---|
| Helix Angle | 45° |
| Spiral Direction | Left-hand / Right-hand (see variant options) |
| Tooth Count | See variant options (10–60 teeth) |
| Bore Diameter | See variant options (8–20 mm / 0.31–0.79 in) |
| Hub Style | Stepped bore hub |
| Material | Carbon steel |
| Pressure Angle | 20° (typical) |
| Finish | See variant options |
| Quantity per Order | 1 PCS |
Modulus determines the tooth size and load capacity. Modulus 1 suits light-duty robotics and small mechanisms. Modulus 1.5 and 2 cover mid-range CNC and automation drives. Modulus 3 is suited for heavy motor transmission with higher torque demands. Match the modulus to your mating gear — mismatched moduli will not mesh correctly.
Yes. Helical gears on parallel shafts must be of opposite hand — a left-hand gear meshes with a right-hand gear of the same modulus and helix angle. If you are replacing a single gear in an existing assembly, identify the hand of the existing gear before ordering.
Measure your motor shaft diameter precisely. Common NEMA 17 stepper shafts are 5 mm, NEMA 23 are typically 6.35 mm or 8 mm, and servo motors vary from 8 mm to 20 mm. Select the bore that matches or is closest to your shaft — a keyway or set screw can be used to secure the gear on the shaft.
Carbon steel helical gears at 45° helix angle provide good load distribution across multiple teeth simultaneously, making them well-suited for continuous-duty CNC axis drives at moderate speeds and loads. For very high-speed or high-load applications, verify the specific modulus and tooth count against your torque and speed requirements.
Carbon steel is susceptible to surface oxidation in humid or wet environments. For outdoor or high-humidity applications, apply a light machine oil or grease to the gear teeth and bore, or consider a protective coating. Regular lubrication will extend service life significantly.
Gear ratio = number of teeth on driven gear ÷ number of teeth on driving gear. For example, a 30-tooth driven gear paired with a 15-tooth driving gear gives a 2:1 reduction ratio. The center distance between shafts = (teeth of gear 1 + teeth of gear 2) × modulus ÷ 2.
The stepped bore hub is designed to accommodate standard shaft fits. Whether a keyway slot is pre-cut depends on the specific variant — Contact us to confirm keyway availability for your selected bore size. A set screw arrangement is a common alternative for securing the gear to the shaft.
