1 Module 45# Steel Spur Gear 15T-46T 1M Metal Pinion Gear 4-20mm Bore For Motor

The tooth count determines your gear ratio when meshed with a mating gear. Divide the driven gear tooth count by the driving gear (pinion) tooth count to get the ratio. For example, a 15T pinion driving a 45T gear gives a 3:1 reduction. Lower tooth counts on the pinion increase torque output; higher tooth counts reduce speed reduction. Match the module (1M) of both gears for proper mesh.

Measure your motor or drive shaft diameter with a caliper before ordering. Available bores include 4, 5, 6, 6.35 (1/4 in), 7, 8, 10, 11, 12, 12.7 (1/2 in), 14, 15, 16, 17, 18, 19, and 20 mm. For a secure fit, the bore should match the shaft diameter exactly. If you plan to use a set screw or keyway, confirm the hub wall thickness is sufficient for your tooth count.

Step-hub variants have an extended cylindrical hub section (the "step") that protrudes beyond the gear face, providing a longer shaft engagement length. This is useful in cantilevered installations, high-torque applications, or where the gear must be positioned away from a bearing or housing wall. Step depths range from 17 mm to 38 mm depending on the variant. If your design does not require extended engagement, a standard (non-step) variant is sufficient.

These gears are machined from 45# medium-carbon steel, which has a tensile strength typically in the 600–800 MPa range in the as-machined condition. Actual load capacity depends on tooth count, face width, operating speed, lubrication, and application duty cycle. For high-cycle or shock-load applications, consider whether surface hardening (e.g., induction hardening) would be appropriate for your design — contact us to confirm material treatment options.

45# carbon steel has limited inherent corrosion resistance. For indoor, dry, or lightly lubricated environments, the material performs well with standard gear oil or grease lubrication. For humid, wet, or chemically exposed environments, consider applying a protective coating (e.g., zinc plating, black oxide, or grease packing) or contact us to discuss alternative material options.

Yes — any gear or rack manufactured to the 1M metric module standard with a 20° pressure angle will mesh correctly with these gears. Confirm that both the module and pressure angle match. If your existing gear uses a different module (e.g., 0.8M, 1.5M, 2M) or a different pressure angle, the gears will not mesh properly and must not be used together.

Yes. These 1M steel spur gears are well-suited for desktop CNC router axis drives, 3D printer extruder or Z-axis gearboxes, robotic arm joints, and small conveyor drive trains. Select the tooth count that achieves your target gear ratio and the bore that matches your motor shaft. For very high-speed or precision positioning applications, verify backlash requirements against the gear's tooth tolerance class.