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When a slipping or undersized gear throws off your entire motion-control build, every axis suffers. Makers, CNC builders, and automation engineers who need repeatable, backlash-minimized power transfer rely on accurately machined spur gears — not off-spec castings. These 2.5 module pinion spur gears are designed for builders who demand dimensional consistency across every tooth.
Each gear is CNC-machined from #45 carbon steel with a no-step bore profile, available in tooth counts from 19T to 29T (module 2.5). Outer diameters range approximately from 52.5 mm (≈ 2.07 in) for 19T up to 77.5 mm (≈ 3.05 in) for 29T, with face widths typically 20–25 mm (≈ 0.79–0.98 in). Sold individually (1 Pcs per order).
Typical applications include CNC router X/Y-axis rack-and-pinion drives, robotic arm joint transmission, conveyor indexing systems, and DIY gearbox builds requiring a 2.5M standard pitch. Long-tail use cases: "2.5 module steel spur gear for CNC router", "45 steel pinion gear robotics", "no-step bore spur gear automation".
| Module | 2.5M |
|---|---|
| Material | #45 Carbon Steel |
| Tooth Count Options | 19T, 22T, 26T, 27T, 28T, 29T |
| Outer Diameter (OD) | See variant options |
| Bore Diameter | See variant options |
| Face Width | Typically 20–25 mm (≈ 0.79–0.98 in) |
| Pressure Angle | 20° |
| Bore Profile | No-step (smooth continuous bore) |
| Finish | Natural steel / lightly oiled |
| Packing Quantity | 1 Pcs |
| Weight | See variant options |
Select the 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 19T pinion with a 38T gear gives a 2:1 reduction. Use smaller tooth counts (19T–22T) for higher reduction ratios and larger counts (26T–29T) for closer to 1:1 drives or overdrive setups.
The bore diameter varies by tooth count variant. Please refer to the variant options or contact us to confirm the exact bore size before ordering. The no-step bore design allows for set-screw or keyway retention depending on your shaft configuration.
#45 carbon steel provides solid tensile strength suitable for CNC router X/Y-axis rack-and-pinion applications under typical cutting loads. For very high-speed or heavy-duty industrial applications with continuous shock loading, consider whether a hardened or alloy steel gear would better suit your torque requirements.
#45 carbon steel is not inherently stainless. The gears are lightly oiled for transit protection. For environments with moisture, coolant exposure, or outdoor use, we recommend applying a rust-inhibiting coating, grease, or considering stainless steel alternatives for your application.
Yes — as long as the mating component is also Module 2.5 (2.5M) with a 20° pressure angle, these gears will mesh correctly regardless of brand. Always verify the module and pressure angle of your existing rack or mating gear before purchasing.
Each variant is sold individually (1 Pcs per line item). To order multiple tooth counts, simply add each desired variant to your cart separately. There is no minimum order quantity per variant.
Module is the metric standard for gear tooth size, defined as the pitch diameter divided by the number of teeth. A Module 2.5 gear has a tooth pitch of 2.5π mm (≈ 7.85 mm). Diametral Pitch (DP) is the imperial equivalent — Module 2.5 is approximately 10.16 DP. These gears use the metric Module 2.5 standard and should only be paired with other 2.5M components.
