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When a stripped plastic gear or an undersized pinion brings your project to a halt, you need a drop-in replacement that won't let you down again. These stainless steel spur gears are engineered for makers, robotics builders, CNC hobbyists, and small-machine designers who require reliable, corrosion-resistant power transmission without custom machining.
Each gear is machined from stainless steel and offered in three metric module sizes — Module 1, Module 1.5, and Module 2 — spanning tooth counts from 12 to 120 teeth. Bore diameters range from 6 mm (0.24 in) up to 25 mm (0.98 in), with most sizes available in plain-bore or keyway configurations (3 mm, 4 mm, 5 mm, 6 mm, or 8 mm keyways depending on bore size). Gear face width and overall diameter scale proportionally with module and tooth count per standard metric gear geometry.
Typical use cases include motor pinion replacement in DC gearbox drives, stage-reduction geartrains for CNC router Z-axes, open-frame conveyor drives, and educational robotics platforms where a stainless steel spur gear with keyway bore provides secure shaft engagement without set-screw slip.
| Material | Stainless Steel |
|---|---|
| Module Sizes Available | Module 1 / Module 1.5 / Module 2 |
| Tooth Count Range | 12–120 T (Module 1); 12–30 T (Module 1.5); 15–30 T (Module 2) |
| Bore Diameter Range | 6 mm – 25 mm (0.24 in – 0.98 in) |
| Keyway Options | 3 mm / 4 mm / 5 mm / 6 mm / 8 mm (bore-size dependent) |
| Gear Type | Spur (straight tooth, external) |
| Pressure Angle | 20° (standard metric) |
| Face Width | See variant options |
| Pitch Diameter | See variant options (= Module × Tooth Count) |
| Finish | Machined, natural stainless |
| Quantity per Order | 1 pc (per variant selection) |
Module size determines tooth size and load capacity. Module 1 suits lightweight, high-speed applications (small robots, hobby CNC). Module 1.5 balances size and strength for mid-range drives. Module 2 handles higher torque in slower, heavier-duty setups. Both mating gears must share the same module to mesh correctly.
A keyway bore is strongly recommended for any application with reversing loads, shock loads, or high torque — it prevents the gear from spinning on the shaft. Plain bores (e.g., the 6 mm or 8 mm plain options) are suitable for light-duty or set-screw-secured assemblies where torque is low and direction is constant.
Gear ratio = driven gear teeth ÷ driving gear teeth. For example, pairing a 12-tooth pinion with a 60-tooth gear gives a 5:1 reduction. Both gears must be the same module. Use this product's wide tooth range (12–120 T in Module 1) to achieve ratios from roughly 1:1 up to 10:1 in a single stage.
Stainless steel offers good tensile strength (typically 515–620 MPa for 304-grade) combined with corrosion resistance. It is well-suited for light-to-medium industrial, robotics, and maker applications. For very high-torque or impact-heavy industrial drives, consider whether a hardened alloy steel gear would be more appropriate for your load cycle.
Stainless steel provides inherent corrosion resistance in most environments, including humid workshops, light outdoor exposure, and mild chemical contact. For prolonged immersion or aggressive chemical environments, verify compatibility with your specific media. Periodic light lubrication extends service life regardless of material.
Measure your motor or gearbox output shaft diameter with a caliper. Select the variant whose bore matches — for example, a 6 mm shaft needs the "6mm" bore variant, while an 8 mm shaft with a 3 mm keyway slot needs the "8mm + 3mm Keyway" variant. If your shaft has no keyway, choose the closest plain bore and secure with a set screw or adhesive retainer.
No. Gears of different modules cannot mesh with each other — the tooth profiles and pitches are incompatible. All gears in a meshing pair or gear train must share the same module number. Plan your entire drivetrain around a single module size.
