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When a mismatched or worn pinion gear causes backlash, noise, or premature drivetrain failure, engineers and makers need a reliable drop-in replacement they can trust. These Steel 45# Mod 1 spur pinion gears are designed for builders, robotics integrators, and CNC hobbyists who demand consistent tooth geometry and a secure shaft fit across a wide range of motor configurations.
Each gear is machined from 45# carbon steel, offering a balance of hardness and machinability suited to moderate-to-high load applications. The Mod 1 (1M) tooth profile is the most widely used metric gear standard, with tooth pitch of 1mm per tooth. Available in 40 to 80 teeth and bore diameters from 6mm to 30mm (approximately 0.24 in to 1.18 in), with stepped hub options (Step 25mm to Step 50mm) to accommodate shaft collars and set-screw locking. Each gear ships with a set screw for secure shaft retention.
Typical use cases include DC motor pinion replacement in CNC router Z-axis drives, servo output gear stages in robotic arms, and rack-and-pinion linear actuator assemblies where a 1M module gear is specified. The wide bore range also makes these gears suitable for stepper motor shafts (typically 5–8mm) up to larger servo output shafts (up to 25–30mm).
Machined from 45# medium carbon steel for reliable hardness, wear resistance, and dimensional stability under cyclic loading in motor-driven gear trains.
Module 1 (1M) metric tooth geometry ensures direct interchangeability with any Mod 1 rack, gear, or pinion in your drivetrain — no custom adaptation required.
Choose from 21 tooth count options (40T, 42T, 43T, 44T, 45T, 46T, 47T, 48T, 49T, 50T, 52T, 54T, 55T, 56T, 58T, 60T, 62T, 65T, 70T, 72T, 80T) to dial in your gear ratio precisely.
Bore diameters from 6mm to 30mm (≈0.24–1.18 in), with stepped hub variants (Step 25mm to Step 50mm) for shaft collar clearance and positive axial positioning.
Each gear ships with a set screw pre-tapped into the hub, allowing tool-free alignment and secure locking onto flat-keyed or round motor shafts.
Suitable for CNC machines, 3D printer extruder drives, robotic arm joints, linear actuators, and any motion-control system specifying a 1M spur pinion gear.
| Material | 45# Carbon Steel |
|---|---|
| Module (Mod) | 1 (Mod 1 / 1M) |
| Tooth Count Range | 40T – 80T (21 options) |
| Bore Diameter Range | 6mm – 30mm (≈0.24 in – 1.18 in) |
| Step Hub Options | Step 25mm / 30mm / 35mm / 38mm / 40mm / 50mm (see variant options) |
| Pressure Angle | 20° (standard metric spur gear) |
| Pitch Diameter | Teeth × Module (e.g., 40T × 1M = 40mm PD) |
| Shaft Retention | Set screw included |
| Surface Finish | See variant options |
| Weight | See variant options |
| Quantity | 1 piece per order |
The gear ratio between your motor pinion and the mating gear equals the driven gear's tooth count divided by the pinion's tooth count. A lower tooth count (e.g., 40T) gives a higher speed reduction when paired with a larger gear; a higher tooth count (e.g., 80T) reduces the ratio. Match the tooth count to your required output speed and torque, and confirm the pitch diameter (Teeth × 1mm) fits within your housing clearance.
Measure your motor shaft diameter with a caliper. Select the bore that matches exactly — for example, a 6mm shaft requires the 6mm bore variant. If your shaft has a flat key or D-cut, the set screw will engage the flat for a secure, non-slip fit. For shafts requiring a hub step for collar clearance, choose the appropriate Step variant (e.g., Step 25mm, Step 35mm, Step 40mm).
The Step dimension refers to the length of the hub boss that extends beyond the gear face. For example, "8mm (Step 35mm)" means the bore is 8mm and the hub protrudes 35mm. This stepped hub provides clearance for shaft collars, motor flanges, or bearing housings, and allows precise axial positioning of the gear on the shaft.
45# carbon steel has a tensile strength of approximately 600–700 MPa and is commonly used for moderate-to-high load gear applications. Allowable torque depends on tooth count, face width, operating speed, and lubrication. For precise load ratings in your specific application, calculate using standard AGMA or ISO 6336 gear strength methods, or contact us with your operating parameters for guidance.
45# carbon steel is not inherently corrosion-resistant. For humid, wet, or outdoor environments, we recommend applying a light machine oil or grease coating during installation and periodically re-lubricating. For applications requiring corrosion resistance, consider stainless steel or nylon gear alternatives. These gears are best suited for enclosed, lubricated gear housings or indoor automation equipment.
Yes — any Mod 1 (Module 1) spur gear or rack with a 20° pressure angle will mesh correctly with these pinions. Confirm that your mating component is also Mod 1 (not Mod 0.8, Mod 1.25, or a DP-standard gear, which are not interchangeable). The center distance between mating gears equals (Pinion PD + Gear PD) ÷ 2.
Each order includes one (1) spur pinion gear plus one set screw. If you need multiple gears for a multi-axis machine or paired gear stage, simply increase the quantity at checkout or order multiple variants as needed.
