Spur Gear 45# Steel 1 Mod 44-120 Teeth Motor Gear Transmission Gears Hardened

The gear ratio equals the driven gear's tooth count divided by the driving pinion's tooth count. For example, a 60T wheel paired with a 20T pinion gives a 3:1 reduction — tripling torque while reducing speed by two-thirds. For moderate reductions (2:1 to 3:1), consider 44T–60T wheels. For higher reductions (4:1 to 6:1), 80T–120T wheels paired with a 20T–25T pinion are typical choices.

Measure your motor shaft diameter with calipers. Common sizes: NEMA 17 steppers typically use 5 mm shafts (not available in this listing — see our pinion gear range), NEMA 23 steppers commonly use 6.35 mm or 8 mm shafts, and larger servo or gearbox output shafts often use 10–16 mm. The grub screw allows positional adjustment, but the bore must match the shaft — do not force an undersized bore.

Yes. All gears in this listing follow the standard Module 1 (1 Mod) metric tooth system with a 20° pressure angle. They mesh correctly with any other Mod 1 spur gear, pinion, or rack regardless of brand, provided the center distance is calculated correctly as (T1 + T2) / 2 mm.

45# steel has a tensile strength of approximately 600–700 MPa in the normalized condition. Surface hardening improves tooth contact fatigue resistance. These gears are suited for moderate-load, continuous-duty applications such as CNC axis drives, conveyor indexing, and robotic joint drives. For heavy shock loads or very high RPM applications, consult a gear engineer for a more detailed load analysis.

45# carbon steel has limited inherent corrosion resistance. For indoor, dry, or lightly lubricated environments they perform reliably. In moisture-prone or outdoor environments, apply a light machine oil or grease to the tooth surfaces regularly. For corrosive environments, consider stainless steel or engineering plastic gear alternatives.

The 4-pack is ideal for multi-axis CNC machines or robotic arms where the same gear specification is used on multiple joints or axes. The 10-pack suits production runs, classroom or lab kits, or maintenance stock where having spares on hand avoids downtime. Both multi-pack options offer a lower per-unit cost compared to ordering singles.

No special tools are required. Slide the gear onto the shaft, position it at the desired axial location, then tighten the included grub screw with a hex key (Allen wrench) of the appropriate size. For higher torque applications, a flat ground on the shaft aligned with the grub screw provides more positive retention and prevents rotation under load.