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When a stripped plastic gear or an undersized drive component brings your build to a halt, you need a drop-in metal replacement that holds up under real load. These 45# carbon steel spur gears are designed for hobbyists, robotics builders, CNC enthusiasts, and small-machine engineers who demand dimensional accuracy and repeatable performance from every component in their drivetrain.
Each gear is machined from 45# medium-carbon steel and hobbed to standard metric module tolerances. Three modulus options are available — Mod 1, Mod 1.5, and Mod 2 — with tooth counts ranging from 12 to 100 teeth and face widths of 10 mm (~0.39 in), 15 mm (~0.59 in), or 20 mm (~0.79 in). Outer diameters scale with tooth count and modulus, ranging from approximately 14 mm (~0.55 in) for the smallest 1 Mod / 12T variant up to 102 mm (~4.02 in) for the 1 Mod / 100T variant, with 2 Mod gears reaching 72 mm (~2.83 in) at 34 teeth.
Typical use cases include open-frame robot joint drives where a Mod 1 gear pair keeps the profile compact, CNC axis reduction stages where a Mod 2 gear set handles higher torque without skipping, and DIY conveyor or indexing table builds where a matched modulus pair ensures smooth, low-backlash motion. The standardized module pitch also makes these gears interchangeable with other metric spur gears of the same modulus, simplifying multi-stage gearbox design.
Medium-carbon steel delivers a tensile strength typically in the 600–800 MPa range, resisting tooth deformation under sustained mesh loads that would crack or strip softer alloys.
Mod 1, Mod 1.5, and Mod 2 cover a wide range of torque and speed requirements. Larger modulus = coarser pitch = higher load capacity per tooth.
From compact 12-tooth pinions to large 100-tooth ring-style gears, you can build single-stage ratios from roughly 1:1 up to 1:8 without stacking multiple stages.
10 mm, 15 mm, and 20 mm face widths let you match the gear width to your available shaft span and load distribution requirements.
Gear teeth are hobbed to standard involute profile geometry, ensuring smooth rolling contact, predictable backlash, and quiet operation across the full mesh cycle.
All gears conform to standard metric module dimensions, making them directly interchangeable with other Mod 1, 1.5, or 2 spur gears from any supplier using the same standard.
| Material | 45# Medium-Carbon Steel |
|---|---|
| Gear Type | Spur Gear (External, Straight Tooth) |
| Tooth Profile | Standard Involute (Hobbed) |
| Available Modulus | Mod 1 / Mod 1.5 / Mod 2 |
| Tooth Count Range | 12 – 100 Teeth (see variant options) |
| Face Width (Thickness) | 10 mm / 15 mm / 20 mm (see variant options) |
| Outer Diameter | See variant options |
| Bore | See variant options (customer machining required) |
| Pressure Angle | 20° (standard metric) |
| Surface Finish | See variant options |
| Quantity per Order | 1 Piece |
Modulus determines the size of each tooth relative to the pitch diameter. Mod 1 gears have smaller, finer teeth suited for light loads and compact layouts — common in robotics and small automation. Mod 1.5 is a mid-range choice balancing size and load capacity. Mod 2 gears have larger, stronger teeth and are better for higher-torque applications such as CNC axis drives or conveyor systems. Both mating gears must share the same modulus to mesh correctly.
With tooth counts from 12 to 100, a single gear pair can achieve ratios from approximately 1:1 (equal tooth counts) up to roughly 1:8 (e.g., 12T driving 100T). For higher ratios, a two-stage gearbox using intermediate shafts is recommended.
No. The bore is supplied as a rough or pilot bore and requires customer machining (turning, boring, or broaching) to match your shaft diameter and fit tolerance. This is standard practice for metric module gears sold as blanks or semi-finished components. Please confirm your shaft size and required fit (clearance, transition, or interference) before machining.
45# carbon steel has a typical tensile strength of 600–800 MPa and yield strength around 355–490 MPa in the normalized or quenched-and-tempered condition. For continuous-duty applications, actual load capacity depends on modulus, face width, pitch line velocity, and lubrication. We recommend applying standard AGMA or ISO gear rating methods to verify adequacy for your specific duty cycle.
45# carbon steel is not inherently corrosion-resistant. For outdoor, humid, or washdown environments, apply a suitable lubricant or protective coating (e.g., grease, oil, or zinc-based spray). For applications requiring inherent corrosion resistance, consider stainless steel or plastic gears of the same modulus instead.
Yes — as long as the mating gear uses the same modulus (Mod 1, 1.5, or 2) and the same pressure angle (20°, which is the global standard for metric module gears). Modulus and pressure angle must match; tooth count and face width can differ between the two mating gears.
A wider face distributes load across more tooth surface area, increasing load capacity and reducing contact stress. Choose 10 mm for compact, lightly loaded assemblies; 15 mm for moderate loads where space is limited; and 20 mm for higher-torque drives where shaft span allows. Ensure your shaft and housing can accommodate the selected face width without interference.
