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When a stripped or undersized gear brings your CNC router, 3D printer, or automated conveyor to a halt, the replacement needs to fit right the first time. Engineers, makers, and machine builders who demand dimensional accuracy and consistent torque transmission rely on a gear that is machined to spec — not cast to approximate. These 1 Module 45# steel spur gears are designed for that exact scenario.
Each gear is machined from 45# medium-carbon steel, offering a tensile strength typically in the 600–800 MPa range. The module (m) is 1, meaning the pitch diameter equals the tooth count in millimeters. Tooth counts span 20 to 80 teeth, and inner bore diameters range from 8 mm (0.31 in) to 30 mm (1.18 in) with matching keyway slots — keyway dimensions vary by bore size from 3×1.4 mm up to 8×3.3 mm. Overall gear outer diameters scale proportionally from approximately 22 mm (0.87 in) for 20T up to approximately 82 mm (3.23 in) for 80T.
Typical use cases include CNC motor output shafts requiring a 1M spur gear with keyway bore, robotics joint drive trains needing a compact steel gear with precise tooth profile, and light industrial conveyor or indexing systems where a 45# steel module 1 gear replaces a worn plastic or aluminum component.
Machined from 45# carbon steel for reliable strength, wear resistance, and machinability — suitable for moderate-load drive applications.
Standard 1M involute tooth form ensures accurate mesh with any compatible Module 1 counterpart gear, minimizing backlash and noise.
Each bore includes a precision-cut keyway slot matched to the bore diameter, enabling secure shaft-to-gear torque transfer without slippage.
Select from 20 to 80 teeth to achieve your required gear ratio. Larger tooth counts provide smoother, lower-speed output; smaller counts suit higher-speed applications.
Dimensionally consistent across the range — suitable for CNC routers, stepper motor drives, robotic arms, and light industrial indexing equipment.
Inner hole options from 8 mm to 30 mm with corresponding keyway dimensions, covering a broad range of motor and shaft standards in a single product line.
| Material | 45# Medium-Carbon Steel |
|---|---|
| Module (m) | 1 |
| Pressure Angle | 20° (standard involute) |
| Tooth Count | 20 – 80 teeth (see variant options) |
| Pitch Diameter | Equal to tooth count in mm (e.g., 30T = 30 mm PD) |
| Outer Diameter (approx.) | Tooth count + 2 mm (e.g., 30T ≈ 32 mm OD) |
| Inner Bore Diameter | See variant options (8 mm – 30 mm) |
| Keyway Dimensions | See variant options (3×1.4 mm – 8×3.3 mm) |
| Face Width | See variant options |
| Surface Finish | See variant options |
| Application | CNC motors, robotics, automation, conveyor drives |
The gear ratio between two meshing gears equals the ratio of their tooth counts. For example, pairing a 20-tooth drive gear with a 40-tooth driven gear gives a 2:1 reduction. Choose a smaller tooth count for higher output speed and a larger tooth count for higher torque at lower speed. Confirm the center distance between shafts matches the sum of the two pitch radii (each pitch radius = tooth count ÷ 2 mm for Module 1).
Measure your motor or drive shaft diameter precisely with calipers. Select the bore option that matches your shaft diameter. The keyway dimensions listed in parentheses (e.g., 3×1.4 mm) indicate the width × depth of the keyway slot — verify these match your shaft key before ordering. If your shaft diameter falls between listed options, contact us to confirm the closest fit.
Yes — any two Module 1 spur gears with the same pressure angle (20° standard) will mesh correctly regardless of tooth count. Confirm the module and pressure angle of your existing gear before ordering. These gears are not compatible with Module 0.5, Module 1.5, Module 2, or other module sizes.
45# carbon steel provides a tensile strength typically in the 600–800 MPa range, making these gears suitable for moderate-load CNC, robotics, and light industrial drive applications. For heavy-duty or high-shock-load environments, consider heat-treated or alloy steel alternatives. Actual load capacity depends on tooth count, face width, speed, and lubrication — consult a mechanical engineer for critical load calculations.
45# carbon steel has moderate corrosion resistance. For indoor, dry, or lightly oiled environments, the material performs well. For humid, wet, or chemically exposed environments, apply a rust-inhibiting lubricant or consider stainless steel or plastic gear alternatives. Regular lubrication with gear oil or grease will extend service life significantly.
Yes. These gears are commonly used on stepper and servo motor output shafts in CNC routers, laser cutters, and 3D printer extruder drives. Select the bore size that matches your motor shaft diameter and confirm the keyway dimensions align with your motor shaft key. The Module 1 tooth profile is a standard choice for compact CNC drive trains.
No additional machining is required if you select the bore and keyway size that matches your shaft. The bore and keyway are pre-machined to the dimensions shown in the variant name. If you need a non-standard bore size or a different keyway depth, contact us before ordering to discuss custom options.
