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When your build demands a reliable, metal-tooth gear that won't strip under load, finding the right module and bore combination can be frustrating. Whether you're a robotics hobbyist, RC vehicle builder, or mechanical engineer prototyping a drive train, this 1.5 Mod 45# steel spur gear gives you a ready-to-mount solution with a pre-drilled bore and a fixing screw included — no extra machining required.
Each gear is CNC-machined from 45# medium-carbon steel, offering a good balance of hardness and toughness. Available tooth counts range from 12T to 35T, with bore options of 5mm (~0.197"), 6mm (~0.236"), and 8mm (~0.315"). The 1.5 module pitch means the gear pitch diameter ranges from approximately 18mm (12T) to 52.5mm (35T), keeping the footprint compact for space-constrained assemblies.
Typical use cases include DIY gearbox assemblies for tabletop robots and automation rigs, replacement drive gears for RC cars and crawlers needing a 1.5 mod mesh, and custom torque-reduction stages in maker projects such as motorized camera sliders or conveyor prototypes.
Machined from 45# steel for a solid combination of wear resistance and impact toughness — suitable for moderate-to-high torque drive applications.
Conforms to the 1.5 Mod gear standard, ensuring direct mesh compatibility with any other 1.5 Module gear in your drivetrain without custom adaptation.
Six tooth count variants let you dial in your gear ratio precisely — from the compact 12T pinion up to the 35T wheel for torque multiplication.
Three bore options cover the most widely used shaft diameters in hobby motors, stepper motors, and DC gearmotor outputs — no reaming needed for standard shafts.
Each gear ships with a set screw for secure shaft retention, so you can mount and lock the gear immediately without sourcing additional hardware.
Teeth are CNC-cut to involute profile tolerances, delivering smooth mesh engagement, reduced backlash, and consistent performance across the full tooth count range.
| Module | 1.5 |
|---|---|
| Tooth Count (T) | 12T / 15T / 20T / 25T / 30T / 35T |
| Bore Diameter | 5mm / 6mm / 8mm (see variant options) |
| Pitch Diameter Range | 18mm – 52.5mm (0.71" – 2.07") |
| Material | 45# Medium-Carbon Steel |
| Tooth Profile | Involute, CNC-machined |
| Pressure Angle | 20° |
| Hub / Face Width | See variant options |
| Fixing Method | Set screw (included) |
| Finish | Natural steel / lightly oiled |
| Quantity | 1 piece per order |
Your gear ratio is determined by dividing the driven gear tooth count by the driving gear tooth count. For example, pairing a 12T pinion with a 30T wheel gives a 2.5:1 reduction. Choose a higher tooth count on the output gear for more torque, or a lower count for more speed. If you're replacing an existing gear, match the tooth count exactly.
Measure your motor or shaft diameter with calipers before ordering. Common hobby motor output shafts are 5mm or 6mm; many NEMA 17 stepper motors use a 5mm shaft; larger DC gearmotors often use 8mm. The bore must match your shaft diameter — the included set screw handles retention but cannot compensate for a mismatched bore.
Yes. Any two gears of the same module (1.5 Mod) and the same pressure angle (20°) will mesh correctly regardless of tooth count. Confirm that your existing gear is marked or specified as Module 1.5 / Mod 1.5 before purchasing.
45# medium-carbon steel is significantly harder and more wear-resistant than aluminum alloy gears, and far stronger than nylon or POM plastic gears. It is well-suited for moderate-to-high torque applications. For very high-speed, low-load applications where noise reduction matters, plastic gears may be preferred; for durability under load, steel is the better choice.
45# carbon steel has limited inherent corrosion resistance compared to stainless steel. For indoor or dry-environment use, the light oil finish provides adequate short-term protection. For outdoor or humid environments, we recommend applying a thin coat of grease or anti-rust oil after installation to extend service life.
These gears are suitable for moderate-speed applications typical of robotics, RC vehicles, and DIY automation (generally up to a few hundred RPM at the gear). For very high-speed industrial applications, consult the specific load and speed ratings with an engineer, as surface finish and lubrication become critical factors.
Each listing is for 1 piece (x1 gear) plus the included fixing set screw. If you need multiple gears or a matched pair, simply adjust the quantity at checkout or add multiple variants to your cart.
