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When your motor drive system demands consistent torque transfer without slop or premature wear, the right gear material and tooth geometry make all the difference. Whether you are a robotics builder, CNC hobbyist, or automation engineer, mismatched or low-grade gears cause backlash, noise, and costly downtime. These 1.5 Module spur gears are engineered for DIYers and professionals who need dependable mechanical performance across a wide range of shaft sizes and tooth counts.
Each gear is machined from 45# medium-carbon steel, offering a strong balance of hardness and machinability. The stepped hub design accommodates a set screw for secure shaft locking. Available in tooth counts from 12T to 80T and bore diameters from 5 mm (0.197 in) to 25 mm (0.984 in), with an outer diameter range of approximately 21 mm (0.83 in) for 12T up to approximately 123 mm (4.84 in) for 80T based on 1.5 Module geometry.
Typical use cases include DC motor pinion drives in wheeled robots and RC platforms, lead-screw reduction stages in desktop CNC routers, and gear-train assemblies in automated conveyor or feeder mechanisms — all applications where a 1.5 mod spur gear with set screw delivers repeatable, low-maintenance power transfer.
Machined from 45# medium-carbon steel for a reliable combination of tensile strength and wear resistance, suitable for continuous-duty drive applications.
Twelve tooth-count options let you dial in the exact gear ratio your drive system needs, from fast-spinning pinions to large reduction gears.
The integrated stepped hub and M3–M5 set screw (size varies by bore) lock the gear firmly onto the shaft, preventing rotational slip under load.
Thirteen bore diameter choices — including the common 6.35 mm (1/4 in) imperial size — ensure compatibility with a broad range of motor and gearbox output shafts.
Fully interchangeable with any standard Mod 1.5 gear, rack, or pinion, making it straightforward to integrate into existing or new gear trains.
Suited for robotics, CNC machines, 3D printer extruder drives, conveyor systems, and other light-to-medium duty mechanical assemblies requiring a 1.5 mod spur gear with set screw.
| Module | 1.5 |
|---|---|
| Pressure Angle | 20° |
| Tooth Count (T) | 12T, 15T, 20T, 25T, 30T, 35T, 40T, 50T, 60T, 65T, 70T, 80T |
| Bore Diameter | 5 mm / 6 mm / 6.35 mm / 7 mm / 8 mm / 10 mm / 12 mm / 14 mm / 15 mm / 16 mm / 17 mm / 20 mm / 25 mm |
| Outer Diameter (approx.) | See variant options (calculated as (T + 2) × Module) |
| Hub Style | Stepped hub with set screw |
| Set Screw Thread | See variant options |
| Material | 45# Medium-Carbon Steel |
| Finish | Natural / lightly oiled |
| Gear Type | Spur Gear (straight tooth) |
| Face Width | See variant options |
| Weight | See variant options |
Select your tooth counts based on the gear ratio you need. Divide the driven gear tooth count by the driving (pinion) gear tooth count to get the reduction ratio. For example, pairing a 20T pinion with a 60T gear gives a 3:1 reduction. Smaller tooth counts (12T–20T) are typically used as motor pinions for speed reduction, while larger counts (50T–80T) serve as the driven gear in the pair.
Measure your motor or gearbox output shaft diameter with a caliper. Choose the bore that matches exactly — a loose bore will cause vibration and wear even with a set screw. If your shaft is imperial (e.g., 1/4 inch), select the 6.35 mm bore option. Common hobby motor shafts are 5 mm, 6 mm, or 8 mm.
45# steel offers a tensile strength of approximately 600–800 MPa, making these gears suitable for light-to-medium continuous-duty applications such as robotics, CNC axis drives, and conveyor systems. For heavy shock loads or very high-speed applications, consider whether a hardened or alloy steel gear would be more appropriate for your specific torque and RPM requirements.
45# carbon steel has moderate corrosion resistance. The gears are supplied with a light oil coating to prevent surface rust during storage and transit. For humid or outdoor environments, apply a gear lubricant or grease regularly, or consider a protective coating. They are not recommended for submerged or highly corrosive environments without additional protection.
Yes. Any gear marked as Module 1.5 (Mod 1.5) with a 20° pressure angle will mesh correctly with these gears, regardless of brand. This includes 1.5 Module racks, helical gears of the same module (with some limitations), and other spur gears. Always verify the pressure angle matches — mixing 14.5° and 20° pressure angle gears will cause poor mesh and rapid wear.
Slide the gear onto the shaft and position it at the desired axial location. Use the appropriate hex key (Allen key) to tighten the set screw against the shaft. For a more secure connection, consider filing a small flat on the shaft at the set screw contact point — this prevents the gear from rotating or walking axially under load. Do not overtighten, as this can deform the bore or strip the set screw thread.
For a 1.5 Module gear, the outer diameter (OD) is calculated as (Tooth Count + 2) × 1.5 mm. For example: 12T → OD ≈ 21 mm; 20T → OD ≈ 33 mm; 40T → OD ≈ 63 mm; 80T → OD ≈ 123 mm. Use this formula to verify the gear fits within your housing or frame before ordering.
