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When your CNC router, robotic arm, or motorized drive system demands repeatable, low-backlash power transfer, a poorly matched gear becomes the weakest link in the chain. Engineers, makers, and automation integrators who need a reliable 1.5 Mod spur gear in a wide tooth-count range will find this series covers everything from compact 12-tooth pinions to large 120-tooth drive wheels in a single consistent product line.
Each 1.5 Mod spur gear is machined from 45# medium-carbon steel, delivering a balance of hardness and machinability suited to moderate-to-heavy load applications. The module (Mod) is 1.5 mm, meaning each tooth pitch is 1.5π mm (approximately 4.71 mm / 0.185 in). Tooth counts span 12T through 120T, with outer diameters ranging from approximately 21 mm (0.83 in) for the 12T up to approximately 183 mm (7.2 in) for the 120T. Bore diameter and keyway dimensions vary by tooth count — see variant options for exact bore specs.
Typical use cases include: DIY CNC gantry drives and rack-and-pinion systems requiring a 1.5M spur gear for smooth linear motion; small-to-medium motor transmission assemblies in conveyor, winch, and rotary indexing equipment; and robotics joint drives where a flat spur gear with a standardized module ensures interchangeability across builds.
Machined from 45# medium-carbon steel for solid load-bearing capacity and resistance to deformation under sustained torque in motor transmission applications.
Fully interchangeable with any 1.5 Mod gear, rack, or pinion. Consistent tooth profile ensures smooth mesh and predictable gear ratios across your drivetrain.
92 tooth-count options in a single product line let you dial in the exact gear ratio you need — from high-speed small pinions to large reduction drive wheels.
Straight-cut flat spur gear geometry delivers efficient power transfer with minimal axial thrust, ideal for parallel-shaft motor transmission and CNC drive systems.
Each gear features a precision-machined center bore sized to the tooth count. Keyway slot included on most sizes for positive shaft engagement without slippage.
Each variant ships as a single gear piece, letting you mix tooth counts to build custom gear trains without paying for quantities you don't need.
| Module (Mod) | 1.5 mm |
|---|---|
| Tooth Count Range | 12T – 120T (see variant options) |
| Pressure Angle | 20° |
| Material | 45# Medium-Carbon Steel |
| Gear Type | Flat Spur Gear (straight-cut) |
| Outer Diameter | See variant options |
| Bore Diameter | See variant options |
| Keyway | See variant options |
| Face Width (Hub Thickness) | See variant options |
| Surface Finish | Natural steel (uncoated) |
| Packing Quantity | 1 piece per order |
Determine your required gear ratio first: divide the driver tooth count by the driven tooth count to get the ratio. For example, a 20T driving a 60T gear gives a 3:1 reduction. Then confirm the resulting outer diameters fit within your housing or frame clearance. Use the 1.5M formula: Outer Diameter (mm) = (Tooth Count + 2) × 1.5.
45# steel (equivalent to SAE 1045) has a tensile strength of approximately 600–700 MPa in the normalized condition. It handles moderate-to-heavy loads in low-to-medium speed motor transmission applications. For high-cycle or high-impact loads, consider heat-treated or alloy steel gears. Actual load capacity depends on tooth count, face width, speed, and lubrication.
45# steel is not inherently corrosion-resistant. For indoor, dry, or lightly oiled environments these gears perform well without additional treatment. For humid, wet, or outdoor applications, apply a light machine oil or grease coating, or consider stainless steel or nylon gears instead. Periodic re-lubrication is recommended for long service life.
Yes — any standard 1.5 Module (1.5M) rack, pinion, or spur gear with a 20° pressure angle will mesh correctly with these gears. Confirm the module and pressure angle match your existing components. Module and pitch are not interchangeable (metric module ≠ diametral pitch), so do not mix with imperial DP gears.
Bore diameter varies by tooth count and is listed in the variant detail page or product drawings. Measure your shaft diameter with calipers before ordering. If the standard bore is slightly undersized, a machinist can open it to your exact shaft size. Do not force-fit a gear onto an oversized shaft as this can crack the hub.
Yes. Steel spur gears should be lubricated with a suitable gear oil or grease to reduce wear and heat buildup. For open-gear applications, a spray-on open-gear lubricant or lithium grease works well. For enclosed gearboxes, use the oil viscosity recommended for your operating speed and load. Re-lubricate at regular maintenance intervals.
Yes. The 1.5 Mod spur gear series is well-suited for CNC router rack-and-pinion drives, rotary axis drives, and similar motion-control applications. For 3D printer extruder drives, smaller module gears (0.5M–1M) are more common, but these 1.5M gears work well for larger-format machines or Z-axis lead screw coupling stages where higher torque is needed.
