0.5M 20-24T Spur Gears Steel Pinion Gears Metal Spur Transmission Gear 45 Steel

The tooth count determines your gear ratio when paired with a mating gear. A 20T pinion driving a 40T gear gives a 2:1 reduction. If you need a specific speed or torque ratio, divide the driven gear's tooth count by the driving gear's tooth count. For most compact robotics and CNC builds, 20T–24T pinions are common driver gears paired with larger driven gears.

Match the bore diameter to your shaft diameter exactly. Common stepper motor shafts are 5 mm; many hobby DC motors use 3–6 mm shafts. The 6.35 mm bore corresponds to a standard ¼-inch shaft used in some servo and gear motors. If your shaft is slightly undersized, a set screw or keyway can compensate — but the bore must be equal to or larger than the shaft.

45 steel spur gears at 0.5M module are rated for light-to-medium duty torque transmission. They perform well in robotics joints, small CNC drives, and 3D printer extruder gearboxes. They are not intended for high-shock industrial machinery or continuous heavy-load applications. For higher torque, consider larger module gears or hardened steel variants.

45 steel is a carbon steel and will oxidize if exposed to moisture without protection. For indoor or dry-environment use, a light coat of machine oil or grease on the tooth faces is sufficient. For humid or outdoor environments, consider applying a rust-inhibiting lubricant or using stainless steel gears instead.

Yes. Module 0.5 is an internationally standardized gear pitch (ISO 54). Any two gears of the same module and pressure angle (20°) will mesh correctly regardless of brand, as long as tooth count and center distance are calculated properly. These gears follow standard 0.5M geometry.

For a single prototype or repair, the 1-piece or 5-piece pack is most economical. For small production runs of 5–20 units, the 10- or 15-piece packs offer a better per-unit price. If you're stocking spares or running a batch of 20+ assemblies, the 30- or 50-piece packs provide the lowest cost per gear. Check the price tiers shown in the variant selector above.

Yes. 0.5M steel spur gears are commonly used in compact extruder gearboxes and filament drive mechanisms. The 20T–24T range pairs well with larger driven gears to achieve the torque multiplication needed for reliable filament grip. Ensure the bore matches your motor shaft and that the gear fits within your extruder's housing clearance.