3 Mod 10-31 Teeth Spur Gears Transmission Gear Pinion Thickness 30mm 45# Steel

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3 Mod 10-31 Teeth Spur Gears Transmission Gear Pinion Thickness 30mm 45# Steel

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Choose Model: 3M 10T

Packing Quantity: 1 pcs

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$19.65 USD

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In stock (500 units), ready to be shipped

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3 Mod Spur Gears — Precision 45# Steel Pinions for Reliable Power Transmission

When your DIY automation project demands consistent torque transfer without slippage or premature wear, the gear material and tooth geometry make all the difference. Hobbyists, makers, and small workshop engineers building CNC routers, conveyor systems, or robotic arms need spur gears they can trust to mesh cleanly and hold up under load — these 3 Mod 10–31 Teeth Spur Gears are engineered for exactly that.

Each gear is machined from 45# medium-carbon steel, a material known for its balanced hardness and machinability. The module is 3 (Mod 3), with a face width (thickness) of 30mm (approximately 1.18 inches). Tooth counts span from 10T to 31T, giving you a wide selection of gear ratios in a single consistent standard. The bore diameter and keyway dimensions vary by tooth count — see variant options for exact bore specs.

These 3 Mod spur gears are well-suited for DIY CNC rack-and-pinion drives, motorized linear actuator systems, rotary indexing tables, and light industrial conveyor gear trains. Whether you are building a custom gearbox for a 3D printer upgrade or a reduction drive for a stepper motor project, the Mod 3 standard ensures broad compatibility with off-the-shelf racks and mating gears.

⚙️ Compatibility: Designed to mesh with any standard Module 3 (Mod 3) spur gear, rack, or pinion. Verify bore diameter and keyway dimensions against your shaft specs before ordering.

✅ Key Features of These 3 Mod Spur Gears

🔩45# Steel Construction — Medium-carbon steel delivers a strong balance of tensile strength and wear resistance for demanding drive applications.
📐Module 3 Standard — Mod 3 tooth geometry ensures direct interchangeability with standard Mod 3 racks, pinions, and mating gears across your drivetrain.
📏30mm Face Width — A generous 30mm (1.18 in) tooth thickness distributes load evenly and reduces edge stress in high-torque applications.
🎯Wide Tooth Count Range — Available from 10T to 31T, enabling a broad selection of gear ratios for speed reduction or torque multiplication in your build.
🔄Consistent Machining Tolerance — Teeth are cut to standard involute profile tolerances for smooth, low-noise meshing and minimal backlash in precision motion systems.
📦Flexible Pack Quantities — Order 1, 2, or 3 pieces per listing to match your project needs and reduce per-unit cost on multi-gear builds.

📐 Technical Specifications — Mod 3 Spur Gears

Module (Mod)	3
Tooth Count Range	10T – 31T (see variant options)
Face Width (Thickness)	30 mm (1.18 in)
Material	45# Medium-Carbon Steel
Tooth Profile	Standard Involute, 20° Pressure Angle
Pitch Diameter	See variant options (Mod × Teeth)
Bore Diameter	See variant options
Keyway	See variant options
Surface Finish	Natural steel (uncoated)
Packing Quantity	1 pcs / 2 pcs / 3 pcs

❓ Frequently Asked Questions

How do I choose the right tooth count for my project?

The tooth count determines your gear ratio. Divide the driven gear teeth by the driving gear teeth to get the ratio. For example, pairing a 10T pinion with a 30T gear gives a 3:1 reduction. Choose a smaller tooth count for higher speed output and a larger tooth count for more torque. All options in this listing share the same Mod 3 standard, so any two can mesh together.

What is the pitch diameter for each tooth count?

For Module 3 gears, pitch diameter = Module × Tooth Count. For example, a 3M 10T gear has a pitch diameter of 30mm, a 3M 20T gear has 60mm, and a 3M 30T gear has 90mm. Use this formula to calculate center distance between meshing gears: (PD1 + PD2) ÷ 2.

What is 45# steel and how strong is it?

45# steel is a medium-carbon structural steel with a carbon content of approximately 0.42–0.50%. It offers a tensile strength of roughly 600–800 MPa in normalized condition and can be further hardened by quenching and tempering. It is widely used for gears, shafts, and machine parts where moderate strength and good machinability are required.

Are these gears corrosion-resistant?

45# steel is not inherently corrosion-resistant. These gears are supplied with a natural steel finish. For outdoor or humid environments, we recommend applying a light machine oil, grease, or a rust-inhibiting coating after installation. For applications requiring corrosion resistance, consider stainless steel or nylon alternatives.

Will these mesh with my existing Mod 3 rack or gear?

Yes — as long as your existing rack or mating gear is also Module 3 with a standard 20° pressure angle involute profile, these gears will mesh correctly. Module (Mod) is the international standard for gear tooth sizing; gears of the same module are interchangeable regardless of brand, provided the pressure angle matches.

How do I verify the bore diameter fits my shaft?

Bore diameter varies by tooth count. Please refer to the variant detail or contact us to confirm the exact bore size for your selected tooth count before ordering. If your shaft diameter does not match the standard bore, the gear can typically be re-bored by a local machine shop to your required dimension.

Can I use these gears for a CNC rack-and-pinion drive?

Yes. Mod 3 spur gears are a common choice for DIY CNC rack-and-pinion systems. Pair the pinion gear with a standard Mod 3 steel or nylon rack. Smaller tooth counts (10T–14T) are typically used as pinions on CNC axes for compact drive assemblies. Ensure your motor shaft matches the bore diameter of the selected gear.

🛒 Select your tooth count (Choose Model) and packing quantity above, then add to cart.