0.5M 30T-38T Spur Gears Steel Pinion Gears Metal Spur Transmission Gear 45 Steel

The tooth count determines your gear ratio when meshed with a pinion or another spur gear. A lower tooth count (e.g., 30T) on the driven gear produces a higher speed output; a higher tooth count (e.g., 38T) produces more torque at lower speed. Match the tooth count to your desired ratio and ensure the mating gear is also 0.5M module.

Measure your motor shaft or axle diameter precisely before ordering. Available bores are 4mm, 5mm, 6mm, 6.35mm (1/4 inch), 8mm, and 10mm. The bore should match your shaft diameter exactly — a loose fit will cause slop and vibration, while an oversized shaft will not fit. If your shaft is imperial (e.g., 1/4 in = 6.35mm), select the 6.35mm bore option.

Yes. Module 0.5M is a standardized metric gear specification. These steel spur gears will mesh correctly with any other 0.5M spur gear regardless of material, as long as the pressure angle is also 20°. Note that pairing steel gears with softer materials (plastic, brass) will cause the softer gear to wear faster — this is often intentional in designs where the softer gear acts as a sacrificial component.

45 steel is a medium-carbon steel with significantly higher tensile strength and hardness than engineering plastics (e.g., POM/Delrin) or zinc alloy (Zamak). It resists stripping under shock loads and maintains dimensional accuracy over repeated load cycles. For applications with continuous torque or impact loads — such as RC drivetrains or robotic joints — steel is the appropriate choice over plastic or die-cast alternatives.

45 steel is not inherently corrosion-resistant. For indoor or dry environments, a light machine oil or grease on the tooth faces is sufficient for lubrication and basic protection. For humid or outdoor environments, apply a corrosion-inhibiting grease or consider periodic re-lubrication. If long-term corrosion resistance is critical, look for gears with a surface treatment such as zinc plating or black oxide — contact us to confirm current finish options.

Teeth height (face width) refers to how wide the gear tooth is along the shaft axis. A 5mm face width distributes the load over a larger contact area, making it better suited for higher torque or heavier-duty applications. A 3mm face width is lighter and more compact, suitable for low-torque or space-constrained designs such as small RC cars or lightweight robotic linkages. Choose 5mm if you are unsure — it provides more margin for load variation.

Each variant is a specific combination of tooth count, bore diameter, teeth height, and quantity. To order multiple combinations, add each variant to your cart separately. Bulk quantity options (5, 10, 20, 30, 40 pcs) are available per variant for workshop stocking or production use.