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When a slipping or undersized gear brings your CNC router, conveyor, or robotic arm to a halt, the cost is more than downtime — it's lost confidence in your build. Engineers, makers, and maintenance professionals who need a reliable, drop-in Module 2.5 spur gear turn to this C45 steel cogwheel series for its consistent tooth geometry and hardened flat face that holds up under sustained load.
Each gear is machined from C45 medium-carbon steel and features a hardened flat face for improved wear resistance. The module is 2.5 (metric standard), with tooth counts spanning 12 to 100 teeth. Pitch diameter ranges from approximately 30 mm (1.18 in) for the 12-tooth pinion up to 250 mm (9.84 in) for the 100-tooth gear, giving you a wide selection for matching gear ratios across shaft sizes. Bore diameter and keyway dimensions vary by tooth count — see variant options for exact bore specs.
Typical use cases include motor pinion drives on CNC milling machines and laser cutters, reduction stages in conveyor and packaging line gearboxes, and torque-transmission assemblies in robotics and automation rigs where a standard Module 2.5 spur gear cogwheel must mesh cleanly with an existing rack or mating gear.
C45 Medium-Carbon Steel Construction — Offers a solid balance of machinability and tensile strength, suitable for moderate-to-high torque drive stages without the cost of alloy steel.
Hardened Flat Face — Surface hardening increases tooth surface hardness to resist pitting and wear under cyclic mesh loads, extending service life compared to unhardened equivalents.
Module 2.5 Metric Standard — Conforms to the ISO/DIN Module 2.5 tooth profile, ensuring accurate mesh with any standard Mod 2.5 rack or mating gear without custom modification.
Wide Tooth-Count Range (12–100 Teeth) — A single product family covers pinion-to-wheel ratios from approximately 1:1 up to 1:8, reducing the need to source gears from multiple suppliers.
Available in 1, 2, or 5-Piece Quantities — Order a single replacement pinion or stock a set of five for a production line — quantity pricing is built into the variant matrix.
Broad Application Compatibility — Suited for CNC machines, conveyor drives, robotic joints, packaging equipment, and general industrial gearbox stages requiring a standard Module 2.5 spur gear motor pinion.
| Module | 2.5 (Metric) |
|---|---|
| Tooth Count Range | 12 to 100 teeth (see variant options) |
| Material | C45 Medium-Carbon Steel |
| Surface Treatment | Hardened flat face |
| Pressure Angle | 20° |
| Pitch Diameter | Module × Teeth (e.g., 2.5 × 20 = 50 mm / 1.97 in) |
| Gear Type | Spur Gear (straight tooth) |
| Bore Diameter | See variant options |
| Face Width | See variant options |
| Keyway | See variant options |
| Finish | Natural steel / lightly oiled |
| Quantity Options | 1 pcs / 2 pcs / 5 pcs |
Select your tooth count based on the gear ratio you need and the center distance between shafts. Divide the desired ratio by 1 to get the tooth-count ratio (e.g., a 4:1 reduction with a 12-tooth pinion requires a 48-tooth wheel). Use the formula: Center Distance = (T1 + T2) × Module / 2, where T1 and T2 are the tooth counts of the two meshing gears.
C45 steel has a typical tensile strength of 600–800 MPa. With a hardened face, surface hardness typically reaches HRC 40–50, which significantly improves resistance to pitting and tooth wear. Actual load capacity depends on tooth count, face width, speed, and lubrication — consult a gear design standard (e.g., AGMA or ISO 6336) for precise calculations for your application.
C45 steel is not inherently corrosion-resistant. For environments with moisture, chemicals, or outdoor exposure, we recommend applying a light machine oil or grease coating during installation and re-lubricating periodically. For highly corrosive environments, consider stainless steel or plastic gears instead.
Yes — as long as your existing rack or mating gear is also Module 2.5 with a 20° pressure angle (the most common standard), these gears will mesh correctly. Always verify the module and pressure angle of your existing components before ordering. Module 2 or Module 3 gears are not interchangeable with Module 2.5.
Bore diameter varies by tooth count. Please refer to the variant detail page or contact us to confirm the bore size for your selected tooth count before ordering. If a custom bore is needed, the gear can typically be re-bored by a local machine shop to your required shaft diameter.
All three quantity options ship the identical gear — only the quantity per order differs. The 2-pcs and 5-pcs options offer a lower per-unit cost and are ideal for production builds, spare-parts inventory, or projects requiring matched gear pairs. Select your preferred quantity in the Amount dropdown above.
Yes. The smaller tooth counts (12–20 teeth) in this series are commonly used as motor pinion gears on stepper and servo motors in CNC and robotics applications. Confirm that the bore diameter matches your motor shaft diameter and that the keyway (if present) aligns with your motor shaft keyway before installation.
