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When your CNC router, robotic arm, or automated conveyor demands smooth, low-noise power transmission, a mismatched or worn pinion gear becomes the weakest link in the entire drivetrain. These left-handed 45° helical gears are engineered for makers, machine builders, and automation engineers who need reliable, drop-in motion-control components without the lead time of custom machining.
Each gear is machined from C45 medium-carbon steel, offering a solid balance of strength, machinability, and wear resistance. Available in Module 1, Module 1.5, and Module 2 standards, with tooth counts ranging from 13 to 30 teeth. Bore diameters span 6 mm (0.24 in) to 30 mm (1.18 in), with keyway options (4 mm, 5 mm, 6 mm, or 8 mm keyway) available on larger bore sizes to ensure positive shaft engagement.
Typical use cases include motor pinion drives on stepper and servo motors in CNC milling machines, left-handed helical gear pairs in gearbox assemblies requiring axial thrust cancellation, and precision rack-and-pinion linear motion systems in 3D printers, laser cutters, and pick-and-place automation equipment.
Machined from C45 medium-carbon steel for dependable tensile strength and surface hardness, suitable for continuous-duty motion-control applications.
The 45° left-handed helix delivers gradual tooth engagement, reducing impact noise and vibration compared to straight-cut spur gears — ideal for high-speed motor pinion applications.
Available in Module 1, Module 1.5, and Module 2, covering a wide range of torque and speed requirements from compact stepper motor pinions to mid-torque servo drives.
Bore sizes from 6 mm to 30 mm, with keyway slots (4–8 mm) on larger bores for positive, slip-free shaft coupling in demanding drive applications.
Select from 13T, 15T, 20T, 26T, or 30T configurations to dial in your gear ratio for the exact speed-torque balance your machine requires.
Standard module sizing ensures direct interchangeability with other Mod 1 / 1.5 / 2 helical gear systems — no custom machining required for most retrofit and repair scenarios.
| Material | C45 Medium-carbon Steel |
|---|---|
| Helix Angle | 45° |
| Hand | Left-handed |
| Module | Module 1 / Module 1.5 / Module 2 (see variant options) |
| Tooth Count | 13T / 15T / 20T / 26T / 30T (see variant options) |
| Bore Diameter | 6 mm – 30 mm (see variant options) |
| Keyway | 4 mm / 5 mm / 6 mm / 8 mm (bore-dependent; see variant options) |
| Pressure Angle | 20° |
| Surface Finish | See variant options |
| Quantity per Order | 1 pc |
The module determines the tooth size and pitch. Module 1 is the smallest and suits compact, high-speed motor pinion drives (e.g., small CNC or 3D printer axes). Module 1.5 balances size and torque for mid-range servo applications. Module 2 is suited for higher-torque, lower-speed drives. Always match the module of the pinion to the mating gear — mixing modules will result in incorrect meshing.
The hand of a helical gear refers to the direction the teeth spiral around the gear body. Left-handed and right-handed gears must be paired together on parallel shafts to mesh correctly. These gears are left-handed (LH); ensure your mating gear is also left-handed if used on a parallel shaft, or right-handed if used in a crossed-axis configuration.
A keyway bore is recommended whenever you need positive, slip-free torque transmission — especially under reversing loads or high-torque conditions. The keyway size is matched to the bore diameter following standard DIN 6885 guidelines: 4 mm keyway for 10–12 mm bores, 5 mm keyway for 14–17 mm bores, 6 mm keyway for 18–22 mm bores, and 8 mm keyway for 24–30 mm bores. Plain (no keyway) bores are available for Module 1 variants in 6–16 mm sizes.
C45 steel has a typical tensile strength of approximately 600–800 MPa in the normalized condition, making it well-suited for moderate-to-high load gear applications. For very high-cycle fatigue or heavy shock loads, consider whether a heat-treated or alloy steel gear would better suit your duty cycle. Contact us if you need material certification details.
C45 steel is not inherently corrosion resistant. For indoor, dry environments these gears perform reliably with standard lubrication. If your application involves moisture, coolant exposure, or outdoor conditions, we recommend applying a suitable gear lubricant or grease, or considering a stainless steel alternative. Contact us to confirm finish options.
Yes, provided the replacement gear matches the original in module, tooth count, helix angle (45°), hand (left-handed), and bore diameter. Measure your existing gear's outer diameter and tooth count, then use the formula: OD = (Z + 2) × m (where Z = tooth count, m = module) to verify the module before ordering.
For most CNC and automation applications, an ISO VG 220 gear oil or a lithium-based grease (NLGI Grade 2) applied to the tooth flanks is suitable. Helical gears generate axial thrust loads, so ensure your bearing arrangement can accommodate thrust in addition to radial loads. Re-lubricate at regular maintenance intervals based on your operating speed and load.
