0.5M 40T-48T Spur Gears Steel Pinion Gears Metal Spur Transmission Gear 45 Steel

The tooth count determines your gear ratio. Pair a lower-tooth-count pinion (driver) with a higher-tooth-count gear (driven) to reduce speed and increase torque. For example, a 40T driving a 40T gives a 1:1 ratio; a 40T driving an 80T gives 2:1 reduction. Select based on your required output speed and torque.

Match the bore diameter to your shaft diameter exactly. Available bores are 5mm, 6mm, 6.35mm (standard 1/4 inch), 8mm, 10mm, and 12mm. If your shaft is metric, select the matching metric bore. For imperial 1/4-inch shafts, choose 6.35mm. A set screw or keyway is typically used to secure the gear — confirm your shaft has a flat or keyway if needed.

Teeth height (face width) affects load capacity and contact ratio. A 5mm face width distributes load over a wider contact area, making it more suitable for higher torque or continuous-duty applications. A 3mm face width is lighter and more compact, suited for low-load or space-constrained designs. Both options use the same 0.5 module pitch and will mesh with standard M0.5 mating gears of the same face width.

Yes — these steel spur gears will mesh correctly with any standard 0.5 module gear regardless of material, as long as the module, pressure angle, and face width are compatible. However, pairing steel with soft plastic gears will accelerate wear on the plastic gear. For longevity, match steel-to-steel or use the steel gear as the driver against a sacrificial plastic driven gear where noise reduction is a priority.

45 steel (medium-carbon steel) offers good tensile strength and can be heat-treated for higher surface hardness. It is generally stronger in bending and more machinable than 304 stainless steel, though it has lower corrosion resistance. For dry indoor mechanical applications, 45 steel is a practical and cost-effective choice. If your environment involves moisture or chemicals, consider adding a protective coating or lubricant.

Yes. 0.5M steel spur gears are widely used in hobby robotics, servo-driven joints, small CNC machines, and extruder drives. Confirm that your motor shaft diameter matches the bore, and that your mating gear is also M0.5. For 3D printer extruder drives, verify the face width and center distance match your existing gear geometry before ordering.

Light lubrication is recommended for steel-on-steel meshing to reduce friction and extend service life. A thin film of grease (such as lithium-based or white grease) applied to the tooth faces at installation is sufficient for most low-to-medium speed applications. Re-lubricate periodically based on your duty cycle and operating environment.