1Mod 12/13/14/15/16/17/18/20-150T Thickness 10mm Transmission Gear 45# Spur Gear

Your gear ratio equals the driven gear's tooth count divided by the driving gear's tooth count. For example, pairing a 20T driver with a 60T driven gear gives a 3:1 reduction. Select tooth counts that achieve your target ratio while keeping both gears within the physical space of your build. The pitch circle diameter (PCD) equals the tooth count multiplied by the module (1mm per tooth for Mod 1), so a 40T gear has a 40mm PCD.

Module (Mod) defines the tooth size — specifically the ratio of pitch circle diameter to tooth count. Mod 1 means 1mm of PCD per tooth. Any two spur gears of the same module and pressure angle will mesh correctly regardless of tooth count. These gears use a standard 20° pressure angle, which is the most common in DIY and light-industrial applications. Verify your existing gears are also Mod 1 / 20° before ordering.

45# carbon steel offers a tensile strength typically in the range of 600–800 MPa after standard heat treatment, making it suitable for moderate-duty automation, robotics, and CNC applications. For continuous high-torque or shock-load environments, consider the tooth count carefully — larger tooth counts distribute load across more teeth simultaneously, improving durability. Contact us to confirm suitability for your specific torque and speed requirements.

45# carbon steel is not inherently stainless. For indoor, dry environments typical of desktop CNC machines, 3D printers, and robotics builds, the material performs well without additional treatment. If your application involves moisture, outdoor exposure, or chemical contact, we recommend applying a light machine oil coating or sourcing a stainless or zinc-plated alternative. Contact us if you need a specific surface treatment.

Bore diameter varies by tooth count and is not uniform across all variants. Please check the variant detail page or contact us with your required shaft diameter before placing your order. Most variants are compatible with set-screw retention; keyway availability depends on the specific tooth count selected.

Yes. Because all variants share the same Mod 1 / 20° involute profile, you can build multi-stage gear trains by chaining multiple gears from this listing. Ensure adequate center-distance spacing between each gear pair (center distance = (T1 + T2) / 2 mm for Mod 1) and that shaft alignment is maintained to prevent premature wear.

Smaller tooth counts (12T–20T) produce compact, lightweight gears suited for high-speed, low-torque stages such as motor pinions. Larger tooth counts (60T–100T) create larger-diameter gears that handle higher torque and provide greater gear reduction when paired with a small driver. For the output stage of a robotic joint or a lead-screw drive, a larger driven gear is typically the right choice.