2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear
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2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear

2 Mod 12-40Tooth Spur Gears pitch 6.28mm 45# Steel With Keyway Pinion Motor Gear

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Price:
$6.24 USD
Stock:
In stock (500 units), ready to be shipped

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Description

2 Modulus Spur Gears — Precision 45# Steel Pinion for DIY Automation

When your motor drive slips, your CNC axis skips, or your conveyor loses sync, the culprit is often a gear that wasn't machined to spec. Makers, workshop builders, and small-batch automation engineers need a spur gear they can trust to mesh cleanly, hold its bore, and survive continuous duty — without sourcing from a specialty distributor.

These 2 Modulus spur gears are machined from 45# medium-carbon steel, heat-treated for surface hardness and core toughness. Tooth count ranges from 12T to 40T, with pitch circle diameters scaling from approximately 24 mm (0.94 in) to 80 mm (3.15 in). Bore options span 8 mm to 35 mm (0.31 in to 1.38 in), with keyway variants available in 4×2 mm, 5×2.5 mm, 6×3 mm, 8×3.5 mm, and 10×4 mm to suit standard shaft keyway standards.

Typical use cases include DIY rack-and-pinion linear actuators for CNC routers, motor-to-shaft power transmission in tabletop automation rigs, and replacement pinion gears in light industrial conveyor drives. The 2 Mod pitch (6.28 mm circular pitch) is a widely adopted metric standard, making these gears compatible with off-the-shelf 2 Mod racks, idlers, and mating gears across most maker and light-industrial platforms.

⚙️ Compatibility: Designed for 2 Modulus (Mod 2) gear systems. Mates with standard Mod 2 racks, pinions, and idler gears. Verify bore diameter and keyway dimensions match your shaft before ordering.

✅ Key Features of These 2 Modulus Spur Gears

🔩
45# Steel Construction

Machined from 45# medium-carbon steel for a balance of machinability, surface hardness, and fatigue resistance suited to continuous-duty power transmission.

📐
Wide Tooth Range: 12T – 40T

Covers common gear ratio requirements from high-speed pinion (12T) to larger driven gears (40T), letting you dial in the exact reduction ratio your project needs.

🕳️
Multiple Bore Sizes: 8 – 35 mm

Bore options from 8 mm to 35 mm accommodate a broad range of motor and shaft diameters without custom machining.

🔑
Keyway Options Available

Choose from No Keyway or standard keyway cuts (4×2, 5×2.5, 6×3, 8×3.5, 10×4 mm) for positive torque transmission and zero shaft slip under load.

📏
Standard Mod 2 Pitch (6.28 mm)

Circular pitch of 6.28 mm conforms to the ISO metric gear standard, ensuring direct interchangeability with Mod 2 racks, idlers, and mating gears from other suppliers.

🏭
Hobbed Tooth Profile

Teeth are hobbed to an involute profile for smooth, low-noise meshing and consistent load distribution across the full tooth face width.

📐 Technical Specifications — 2 Modulus Spur Gears

Module 2 (Mod 2)
Circular Pitch 6.28 mm (0.247 in)
Tooth Count Range 12T – 40T
Bore Diameter Range 8 – 35 mm (0.31 – 1.38 in)
Pitch Circle Diameter Range 24 – 80 mm (0.94 – 3.15 in)
Material 45# Medium-Carbon Steel
Tooth Profile Involute (hobbed)
Pressure Angle 20°
Keyway Options No Keyway / 4×2 mm / 5×2.5 mm / 6×3 mm / 8×3.5 mm / 10×4 mm
Face Width See variant options
Hub Diameter See variant options
Finish See variant options
Quantity per Order 1 pc

❓ Frequently Asked Questions

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

Select tooth count based on your required gear ratio. Divide the driven gear tooth count by the driving (pinion) gear tooth count to get the reduction ratio. For example, a 12T pinion meshing with a 36T gear gives a 3:1 reduction. Smaller tooth counts produce higher speed ratios; larger tooth counts produce more torque multiplication.

What bore diameter should I order?

Measure your motor or shaft outer diameter with calipers before ordering. The bore must match your shaft diameter exactly. If you need a keyway, also confirm the keyway width and depth on your shaft matches one of the available keyway options (4×2, 5×2.5, 6×3, 8×3.5, or 10×4 mm).

Are these gears compatible with Mod 2 racks and other Mod 2 gears?

Yes. These gears conform to the ISO Mod 2 standard with a 20° pressure angle and 6.28 mm circular pitch. They will mesh correctly with any other Mod 2 involute spur gear or rack of the same module and pressure angle, regardless of brand.

How strong are these gears — can they handle continuous duty?

45# steel offers a good balance of tensile strength (typically 600–800 MPa) and surface hardness after heat treatment. These gears are suited for light-to-medium duty continuous operation in DIY automation, CNC, and conveyor applications. For heavy industrial loads or shock loading, consider gears made from alloy steel or with surface hardening treatments.

Do these gears resist corrosion?

45# carbon steel has moderate corrosion resistance. For indoor or dry environments, the bare steel finish is adequate with periodic light lubrication. For humid or outdoor environments, apply a rust-inhibiting grease or consider a zinc-plated or stainless alternative. Do not use in direct water immersion without additional corrosion protection.

Do I need to machine the bore or keyway myself?

No. The bore and keyway are pre-machined to the dimensions shown in the variant options. Simply select the bore diameter and keyway size that matches your shaft, and the gear is ready to install. No additional machining is required for standard shaft sizes.

What is the difference between "No Keyway" and keyway variants?

"No Keyway" gears rely on a set screw or interference fit to secure the gear to the shaft — suitable for light loads or applications where the shaft has no keyway slot. Keyway variants include a machined slot that accepts a standard key, providing a positive mechanical connection that prevents rotation under higher torque loads.

🛒 Select your Tooth Number, Bore Diameter, and Keyway option above, then add to cart.

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