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When a stripped plastic gear brings your RC car, robot arm, or small CNC machine to a dead stop, you need a metal replacement that holds up under real load. These 0.5 Module (0.5M) steel spur pinion gears are engineered for hobbyists, makers, and light-industrial builders who demand consistent mesh, tight tolerances, and corrosion-resistant durability in compact drive trains.
Each gear is machined from 45 steel — a medium-carbon structural steel known for its balance of hardness and toughness — and finished with a smooth bore. Available in 50T, 52T, 55T, and 58T tooth counts, with bore options of 6 mm (0.24 in), 8 mm (0.31 in), 10 mm (0.39 in), and 12 mm (0.47 in). Outer diameter scales with tooth count: typically 26–31 mm (1.02–1.22 in) across the range. Order from 1 to 30 pieces per variant to match your project or stock needs.
Typical use cases include RC car and truck drivetrain upgrades where plastic pinions fail under torque, small robotic joint and actuator assemblies requiring repeatable gear mesh, and DIY CNC or 3D-printer extruder drives where a 0.5M module pitch is specified. Long-tail search terms that describe this product: 0.5 module steel spur gear, 45 steel pinion gear 50T, metal RC car transmission gear replacement.
Medium-carbon 45 steel delivers a reliable balance of surface hardness and core toughness, resisting wear under repeated load cycles in compact gear trains.
Standard 0.5M module ensures direct interchangeability with any mating gear or rack of the same module, simplifying replacement and system design.
Choose 50T, 52T, 55T, or 58T to dial in your gear ratio. More teeth = larger OD and lower speed ratio with a given pinion partner.
Bore sizes of 6, 8, 10, and 12 mm cover the most common shaft diameters in RC, robotics, and light CNC applications — no custom machining required for standard shafts.
Order 1, 5, 10, 15, 20, 25, or 30 pieces per variant. Single-piece sampling or bulk stocking — priced per-unit to reward larger orders.
Each gear is machined to maintain tooth profile accuracy and bore concentricity, reducing vibration and noise in assembled drive systems.
| Module | 0.5M |
|---|---|
| Tooth Count Options | 50T / 52T / 55T / 58T |
| Bore Diameter Options | 6 mm / 8 mm / 10 mm / 12 mm |
| Outer Diameter (approx.) | 26–31 mm (1.02–1.22 in), varies by tooth count |
| Material | 45 Steel (medium-carbon) |
| Pressure Angle | 20° (standard spur gear) |
| Gear Type | Spur (straight tooth) |
| Finish | Machined, natural steel |
| Hub / Face Width | See variant options |
| Available Quantities | 1 / 5 / 10 / 15 / 20 / 25 / 30 pcs |
The tooth count determines your gear ratio and the outer diameter of the gear. A higher tooth count (e.g., 58T) gives a larger OD and a lower speed ratio when paired with a smaller pinion. Match the tooth count to your desired gear ratio and confirm the OD fits within your chassis or housing clearance.
Select the bore that matches your motor or drive shaft diameter exactly: 6 mm, 8 mm, 10 mm, or 12 mm. If your shaft is imperial (e.g., 1/4 in ≈ 6.35 mm), choose the next bore size up and use a set screw or locking collar to secure the gear, or have the bore lightly reamed to fit.
Yes. Module (0.5M) is a universal pitch standard. These steel gears will mesh correctly with any 0.5M plastic, nylon, or metal spur gear of the same module and pressure angle (20°). They are a direct drop-in replacement for worn plastic pinions in RC and robotic systems.
45 steel has a tensile strength typically in the range of 600–800 MPa, significantly higher than engineering plastics (50–100 MPa) and brass (300–500 MPa). For high-torque or high-cycle applications — such as RC car drivetrains or robotic joints — 45 steel gears resist tooth deformation and wear far better than plastic equivalents.
Yes, for best performance and longevity, apply a thin layer of gear grease or light machine oil to the tooth faces before assembly. In enclosed gearboxes, a light grease is preferred. In open-frame applications, a dry-film lubricant or light oil applied periodically will reduce wear and noise.
45 steel is not stainless and will oxidize if exposed to moisture without protection. For outdoor or humid environments, apply a thin coat of machine oil, anti-rust spray, or grease to exposed surfaces. For fully corrosion-resistant applications, consider stainless steel or brass gears instead.
Order a single piece (1 pcs) to verify fit and mesh before committing to a larger quantity. Once confirmed, bulk packs (5, 10, 15, 20, 25, or 30 pcs) offer a lower per-unit cost and ensure you have spares on hand for ongoing projects or production runs.
