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When a stripped or undersized gear brings your build to a halt, the fix demands a part you can trust. These 1 module stainless steel spur gears are engineered for hobbyists, makers, and small-scale machine builders who need reliable, dimensionally consistent pinion gears without sourcing from industrial distributors.
Each gear is machined from stainless steel and offered across a tooth range of 20 to 50 teeth (1 Mod), with bore diameters spanning 8 mm to 20 mm (approx. 0.31"–0.79") and keyway slots sized 3×1.4 mm, 4×1.8 mm, 5×2.3 mm, or 6×2.8 mm depending on bore. Outside diameters scale with tooth count, ranging from approximately 22 mm (0.87") for 20T up to approximately 52 mm (2.05") for 50T.
Typical use cases include DC motor pinion replacement in robotics and automation rigs, gear-train assembly in CNC router Z-axis drives, and custom reduction stages in 3D printer extruder or conveyor systems where a 1 mod stainless steel spur gear with keyway bore is required for positive shaft engagement.
| Module | 1 (Mod 1) |
|---|---|
| Tooth Count Range | 20 – 50 Teeth |
| Material | Stainless Steel |
| Pressure Angle | 20° (standard) |
| Bore Diameter Options | 8 mm / 10 mm / 12 mm / 14 mm / 15 mm / 16 mm / 17 mm / 18 mm / 19 mm / 20 mm |
| Keyway Dimensions | 3×1.4 mm / 4×1.8 mm / 5×2.3 mm / 6×2.8 mm (varies by bore) |
| Outside Diameter | See variant options (scales with tooth count: approx. 22–52 mm) |
| Face Width | See variant options |
| Finish | Natural stainless (uncoated) |
| Quantity per Order | 1 Piece |
Select tooth count based on your required gear ratio. Divide the driven gear's tooth count by the driving gear's tooth count to get the ratio. For example, pairing a 20-tooth pinion with a 40-tooth gear gives a 2:1 reduction. Also confirm that the resulting outside diameter fits within your housing clearance.
Measure your motor or drive shaft diameter precisely with calipers. Select the bore option that matches — for example, an 8 mm shaft requires the 8 mm bore variant. The keyway dimensions are listed per bore size in the specifications table above; confirm your shaft has a matching keyway cut.
Stainless steel offers good tensile strength suitable for light-to-medium duty motor pinion applications such as robotics, small CNC axes, and conveyor drives. For heavy industrial loads or high-RPM continuous duty, verify the gear's rated torque against your application's peak load. Contact us to confirm suitability for demanding cycles.
Stainless steel provides significantly better corrosion resistance than standard carbon steel gears. These gears are suitable for humid indoor environments and light outdoor exposure. For immersion or salt-spray environments, additional sealing or a higher-grade stainless alloy may be advisable.
Yes. Any Module 1 gear — regardless of material — will mesh correctly with these stainless steel Mod 1 spur gears, provided the pressure angle matches (20° standard). Mixed-material pairings are common in robotics where a harder steel pinion drives a softer plastic or aluminum gear to reduce wear on the replaceable component.
The bore includes a keyway slot, but you can still mount the gear on a smooth shaft using a set screw or retaining compound if your application allows it. However, for torque-transmitting motor drives, a matching keyed shaft is strongly recommended to prevent rotational slippage under load.
The format is Bore diameter / Keyway width × Keyway depth. So "8/3×1.4mm" means an 8 mm bore with a 3 mm wide × 1.4 mm deep keyway slot, while "10/4×1.8mm" means a 10 mm bore with a 4 mm wide × 1.8 mm deep keyway. Match both the bore diameter and keyway dimensions to your shaft and key stock.
