1.5 Mod Spur Gear 45# Steel Transmission Gear 50T-80T Teeth With Step Motor Gear

Tooth count determines your gear ratio. Divide the driven gear's tooth count by the driving gear's tooth count to get the reduction ratio. For example, pairing a 50T gear with a 25T pinion gives a 2:1 reduction. Higher tooth counts (70T, 80T) produce greater reduction and more torque output at lower speed; lower counts (50T, 60T) are better for moderate reduction or speed-matching applications.

Match the bore to your motor's output shaft diameter. Common stepper motor shaft sizes: NEMA 17 typically uses 5 mm shafts (not listed — use a 8 mm bore with a sleeve adapter), NEMA 23 commonly uses 6.35 mm or 8 mm shafts, and NEMA 34 commonly uses 12.7 mm or 14 mm shafts. The 8 mm, 10 mm, 12 mm, 15 mm, 16 mm, 17 mm, 20 mm, and 25 mm bore options cover most servo and stepper configurations. If your shaft is metric, select the matching bore directly.

45# medium-carbon steel is a widely used engineering material for power transmission gears in light-to-medium duty applications. It offers good tensile strength (typically 600–800 MPa) and responds well to heat treatment if higher surface hardness is needed. For most DIY CNC routers, 3D printer drives, and small conveyor systems operating at moderate speeds and loads, 45# steel provides adequate strength and wear resistance without the cost of alloy steel.

45# carbon steel is not inherently corrosion-resistant. In humid or wet environments, we recommend applying a light machine oil or grease to the gear teeth and bore after installation. For long-term corrosion protection, consider a zinc-phosphate coating or periodic re-lubrication. If your application requires inherent corrosion resistance, a stainless steel or nylon gear may be more appropriate.

Yes — as long as the mating gear is also Mod 1.5 with a 20° pressure angle, it will mesh correctly regardless of material. Steel-on-plastic pairings are common in noise-sensitive or low-load applications where the plastic gear acts as a sacrificial wear component. Keep in mind that the steel gear will outlast the plastic gear significantly, so plan for periodic replacement of the softer gear.

The step hub is a raised shoulder on the gear bore face with a diameter of 50 mm. It provides a positive axial stop when the gear is pressed or slid onto a shaft, ensuring consistent positioning without relying solely on set screws. This is especially useful in paired-axis builds where both gears must be positioned at the same axial depth for proper mesh alignment.

Order 1 pc if you need a single gear for one axis or to replace a worn gear in an existing drivetrain. Order 2 pcs if you are building a mirrored dual-axis machine (such as a dual-Y-axis CNC gantry), need a spare on hand, or are assembling a gear pair where both gears share the same tooth count and bore. Both quantities ship from the same production batch, ensuring consistent tooth geometry between pieces.