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When your CNC router stalls mid-cut or your robotic arm loses torque due to a worn gear, the root cause is almost always a mismatch between gear module, bore size, and tooth count. Engineers, makers, and small-batch manufacturers who need repeatable, low-backlash power transmission demand components that are dimensionally consistent and mechanically sound — and that is exactly what these Mod 0.8 spur gears are built to deliver.
Each gear is machined from carbon steel and features a stepped pinion hub design for secure shaft engagement. The tooth range spans 15 to 80 teeth across both K-Type (keyway-style hub) and B-Type (plain bore) configurations, with bore diameters from 4 mm to 12 mm (approximately 0.16 in to 0.47 in). Overall gear outer diameters range from approximately 13.6 mm (0.54 in) for a 15-tooth gear up to approximately 65.6 mm (2.58 in) for an 80-tooth gear, based on the 0.8 module standard formula (OD = (T + 2) × M).
Typical use cases include DIY CNC gantry drives, 3D printer extruder gear trains, small robotic joint actuators, motorized camera sliders, and light-duty conveyor indexing systems — anywhere a compact, metric-pitch spur gear with a stepped hub is required for shaft-to-shaft power transfer.
Available from 15 to 80 teeth in a single product family, covering gear ratios from approximately 1:1 to 1:5.3 without switching module standards.
Machined from carbon steel for solid tensile strength and wear resistance, suitable for continuous-duty motion control in dry or lightly lubricated environments.
The integrated step hub provides a positive axial stop for shaft positioning, reducing assembly time and improving concentricity compared to plain-hub gears.
K-Type (15–18 teeth) features a keyway-compatible hub profile; B-Type (20–80 teeth) uses a plain bore suited for set-screw or press-fit shaft retention.
Bore options of 4, 5, 6, 7, 8, 10, and 12 mm match standard metric motor and gearbox output shafts used in NEMA 17, NEMA 23, and similar stepper motor platforms.
Order as a single gear for prototyping or as a 5-piece pack for production builds and spare-parts inventory, with consistent per-unit pricing at volume.
| Module | 0.8 |
|---|---|
| Tooth Count Range | 15 – 80 teeth |
| Hub Type | K-Type (15–18T), B-Type (20–80T) |
| Material | Carbon Steel |
| Bore Diameter Options | 4 mm / 5 mm / 6 mm / 7 mm / 8 mm / 10 mm / 12 mm |
| Outer Diameter (approx.) | (Teeth + 2) × 0.8 mm — e.g., 13.6 mm (15T) to 65.6 mm (80T) |
| Pressure Angle | 20° (standard for Mod 0.8) |
| Hub Style | Stepped pinion hub |
| Surface Finish | See variant options |
| Quantity per Order | 1 PCS or 5 PCS (select via Bore & Amount option) |
| Weight | See variant options |
Select your tooth counts based on the gear ratio you need. Divide the driven gear teeth by the driver gear teeth to get the ratio. For example, pairing a 20-tooth driver with a 40-tooth driven gear gives a 2:1 reduction. This product family covers 15 to 80 teeth, supporting ratios from approximately 1:1 up to 1:5.3 within a single module standard.
K-Type hubs (available on 15, 16, and 18-tooth variants) feature a hub profile designed for keyway shaft engagement, providing positive rotational locking without relying solely on a set screw. B-Type hubs (20 through 80 teeth) use a plain cylindrical bore, typically retained with a set screw or press fit. Choose K-Type when your shaft has a keyway; choose B-Type for standard round shafts.
Match the bore diameter to your motor or gearbox output shaft. Common pairings: 5 mm bore for NEMA 17 stepper motors, 6.35 mm (use 6 mm bore with a light reaming allowance) for some servo motors, 8 mm for NEMA 23 steppers, and 10–12 mm for larger gearbox outputs. Always verify your shaft diameter with calipers before ordering.
Yes. All gears in this listing follow the Mod 0.8 standard (module = 0.8 mm, pressure angle = 20°). They will mesh correctly with any other Mod 0.8 spur gear, rack, or pinion of the same module and pressure angle, regardless of brand, as long as the tooth profiles conform to the standard.
Carbon steel offers solid tensile strength and wear resistance for light-to-medium duty power transmission. For dry or intermittently lubricated environments typical of CNC machines, 3D printers, and small robotic joints, carbon steel gears perform reliably. For high-load, high-speed, or corrosive environments, consider stainless steel or engineering plastic alternatives. Applying a light machine oil or grease to the tooth flanks will extend service life.
Carbon steel has moderate corrosion resistance. In dry indoor environments, surface oxidation is minimal. For humid or outdoor applications, apply a thin coat of machine oil or anti-rust spray periodically. If corrosion resistance is a primary requirement, consider stainless steel gears instead.
Each variant in this listing represents a specific combination of tooth count and bore size. To order multiple combinations, add each desired variant to your cart separately. The 5-PCS pack option is available for most bore/tooth combinations and offers a cost-effective way to stock spares or build multiple identical assemblies.
