Spur Gear 1 Mod Transmission Gear With Step 45#Steel Pinion Motor Gear 25/30/35T

Your tooth count determines the gear ratio when paired with a mating gear. A lower tooth count (25T) on the drive gear produces a higher speed reduction when meshed with a larger gear, while a higher tooth count (35T) reduces the ratio difference. Calculate your desired output speed or torque and select accordingly. If you are replacing an existing gear, match the tooth count exactly.

Measure your motor or drive shaft diameter with calipers. Select the bore option that matches your shaft size exactly — available from 5 mm up to 17 mm. Common motor shaft sizes include 5 mm, 6 mm, 6.35 mm (1/4"), 8 mm, and 10 mm. If your shaft is between listed sizes, contact us to confirm the closest fit.

The step diameter refers to the larger shoulder machined into the bore that seats against a stepped shaft or housing face. Options are 20 mm and 25 mm. Choose the step diameter that matches the shoulder on your shaft or the counterbore in your housing to ensure the gear seats flush and does not wobble under load.

45# medium-carbon steel offers a tensile strength typically in the range of 600–800 MPa after standard heat treatment, making it suitable for moderate-load power transmission in CNC machines, robotics, and DIY gearboxes. For very high-torque or high-speed industrial applications, consider whether a hardened or alloy steel gear would be more appropriate.

45# steel is not inherently corrosion-resistant. For indoor or dry environments, the natural machined surface is adequate. If your application involves moisture, coolant, or outdoor exposure, apply a light machine oil coating or consider a zinc-plated or stainless alternative. Regular lubrication also extends service life significantly.

Yes. These gears follow the standard Mod 1 tooth profile with a 20° pressure angle, so they mesh correctly with any other Mod 1 spur gear, rack, or pinion of the same module. Do not mix with Mod 0.8, Mod 1.25, or other module sizes — mismatched modules will not mesh properly.

Yes. Each variant is available in a 1-piece quantity, so you can order a single gear to verify fit and function before committing to a 3, 5, or 10-piece pack. Simply select your tooth count, bore diameter, step diameter, and "1 Pcs" from the quantity option.