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When your RC car, robotic arm, or small-scale transmission demands a gear that holds tight tolerances without stripping under load, a poorly matched pinion gear becomes the weakest link in the entire drivetrain. Hobbyists, makers, and mechanical engineers who work with compact motor assemblies need a 0.5 module spur gear that fits precisely, meshes cleanly, and resists wear over thousands of cycles.
This 0.5 Mod Brass Spur Gear features 55 teeth machined from solid brass stock, offering a balance of machinability and corrosion resistance. The bore diameter ranges from 4 mm (0.157 in) to 15 mm (0.591 in) across eight size options, with an outer diameter of approximately 28 mm (1.10 in) based on the 0.5 module and 55-tooth geometry. Face width is typically 5–8 mm (0.20–0.31 in); confirm exact dimensions against your variant selection.
Typical use cases include motor-to-shaft coupling in 1:10 and 1:12 scale RC drivetrains, torque transmission in desktop CNC pen plotters, and stage-reduction gearing in small servo-driven robotic joints — all scenarios where a compact 0.5 mod 55-tooth pinion gear must mesh with a matching rack or spur without backlash creep.
Involute tooth geometry machined to 0.5 module standard ensures smooth, low-noise meshing with any compatible 0.5 Mod counterpart gear or rack.
Brass offers natural corrosion resistance, self-lubricating properties under light loads, and easy re-machining if custom bore sizing is needed in your workshop.
Available in bore diameters of 4, 5, 6, 8, 10, 12, 14, and 15 mm to fit a wide range of motor shafts, axles, and drive pins without adapter sleeves.
Order as 1 PCS for prototyping, 2 PCS for paired-stage builds, or 5 PCS for batch production runs and spare-part inventory management.
The 0.5 Mod 55T geometry yields an outer diameter of approximately 28 mm (1.10 in), fitting inside tight motor bays and compact gearbox housings.
Standardized module sizing means this gear can directly replace worn 0.5 Mod 55T gears in existing assemblies without redesigning the gear train.
| Module | 0.5 |
|---|---|
| Number of Teeth | 55T |
| Material | Brass |
| Bore Diameter | 4 / 5 / 6 / 8 / 10 / 12 / 14 / 15 mm — See variant options |
| Outer Diameter (approx.) | ~28 mm (1.10 in) |
| Pitch Diameter (approx.) | ~27.5 mm (1.08 in) |
| Face Width | See variant options |
| Pressure Angle | 20° (standard involute) |
| Gear Type | Spur Gear (Pinion) |
| Finish | Natural brass (uncoated) |
| Packing Quantity | 1 PCS / 2 PCS / 5 PCS — See variant options |
Measure your motor shaft or axle diameter with a caliper. Select the bore size that matches exactly — for example, a 5 mm motor shaft requires the Bore 5 mm variant. If your shaft is between listed sizes, choose the next size up and use a set screw or keyway adapter to secure the gear.
This gear is 0.5 module. Any mating spur gear, rack, or pinion must also be 0.5 module. Mixing modules (e.g., pairing a 0.5 Mod gear with a 0.8 Mod gear) will result in incorrect meshing, excessive noise, and rapid tooth wear.
Brass is well-suited for light-to-medium load applications such as RC drivetrains, robotics, instrumentation, and hobby CNC machines. It offers good wear resistance and natural lubricity. For heavy-load or high-RPM industrial applications, consider steel gears instead. If in doubt, contact us with your torque and speed requirements.
Brass has inherent corrosion resistance and will not rust like steel. In humid or mildly wet environments it performs reliably. For prolonged outdoor or marine exposure, applying a light coat of grease or gear oil will extend service life significantly.
Yes. Because module and tooth count are standardized, this gear is a drop-in replacement for any 0.5 Mod 55T spur gear of the same bore diameter. Verify the face width and hub length of your original gear against the product dimensions to confirm full compatibility before installation.
A two-stage reduction typically requires one gear per stage, so the 2 PCS pack is a convenient starting point. If you are building multiple units or want spares on hand, the 5 PCS pack offers a lower per-unit cost and ensures you have replacements ready without reordering delays.
The gear ratio equals the number of teeth on the driven gear divided by the number of teeth on the driving pinion. For example, pairing this 55T gear with an 11T pinion gives a 5:1 reduction ratio. Adjust your driving pinion tooth count to achieve your target speed and torque output.
