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When a slipping or worn pinion gear brings your motor-driven project to a halt, you need a replacement that fits right and holds up under load. Whether you're a robotics builder, CNC hobbyist, or mechanical engineer sourcing transmission components, this 1 Module 27 Teeth spur gear delivers the dimensional accuracy and material strength your drivetrain demands.
This spur gear is machined from 45# medium-carbon steel, offering a balanced combination of toughness and machinability. With a module of 1 and 27 teeth, the pitch diameter is 27 mm (approximately 1.06 in), and the overall gear diameter is typically 29 mm (approx. 1.14 in). The bore diameter varies by variant — see variant options for exact bore sizing. Each pack contains 20 pieces, making it ideal for batch builds and spare-parts inventory.
Typical use cases include DC motor pinion replacement in robotics arms and automated feeders, gear-train assemblies in small CNC routers and laser engravers, and educational mechatronics kits requiring standardized metric module gears. Long-tail applications such as "1 mod 27 tooth steel spur gear for robot" and "metric module 1 pinion gear 27T" are well served by this component.
| Module | 1 (Mod 1) |
|---|---|
| Number of Teeth | 27 |
| Pitch Diameter | 27 mm (1.06 in) |
| Outside Diameter | 29 mm (1.14 in) |
| Pressure Angle | 20° |
| Bore Diameter | See variant options |
| Face Width | See variant options |
| Material | 45# Medium-Carbon Steel |
| Surface Finish | Corrosion-resistant treated |
| Gear Standard | ISO/DIN Metric Module |
| Pack Quantity | 20 Pcs |
Measure your motor shaft diameter with a caliper before ordering. The bore of the gear must match or be slightly larger than the shaft so a set screw or keyway can secure it. Check the variant options on this listing for available bore sizes and select the one closest to your shaft diameter.
Module (Mod) is the metric standard for gear tooth size. Module 1 means the pitch diameter in millimeters equals the number of teeth — so a 27-tooth M1 gear has a 27 mm pitch diameter. Any two gears of the same module and pressure angle (20° here) will mesh correctly, regardless of tooth count. If your existing gears are labeled M1 or Mod 1, these are compatible.
45# steel (equivalent to AISI 1045) has a tensile strength of approximately 600–700 MPa in its normalized state. It is well-suited for moderate-to-high torque pinion applications such as DC gear motors, stepper drives, and small gearboxes. For very high-shock or high-RPM applications, consider whether a hardened or alloy steel variant would better suit your load requirements.
The gears have a corrosion-resistant surface treatment that provides protection during normal storage and use in moderately humid conditions. For outdoor or wet environments, applying a light machine oil or grease to the tooth surfaces is recommended to extend service life.
Yes, provided your motor's output shaft matches one of the available bore diameters and the mating gear on your drivetrain is also Module 1 with a 20° pressure angle. Confirm the face width and overall length fit within your gearbox housing before installing.
The 20-piece pack is designed for builders, educators, and small-batch manufacturers who need spares on hand or are assembling multiple units. Having extras prevents project downtime when a gear wears or a prototype needs iteration. If you need a smaller quantity, contact us to discuss options.
Typically you will need a hex key (Allen wrench) to tighten the set screw if the gear uses a set-screw bore, or a gear puller and press for interference-fit installations. A caliper is useful for verifying shaft and bore dimensions before assembly. No special tools are required beyond standard workshop equipment.
