3 Modulus Spur Gear 10T - 30T Flat Gear 45 Steel Transmission Gears OD 36-96mm

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3 Modulus Spur Gear 10T - 30T Flat Gear 45 Steel Transmission Gears OD 36-96mm

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By HomeDIYer®

Modulus: 3Modul

Teeth-OD: 10T - OD 36mm

QTY(Pcs): 1

Price:

$16.86 USD

Stock:

In stock (500 units), ready to be shipped

Quantity:

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Module 3 Spur Gear — Precision 45 Steel Transmission Gears for Demanding Drive Systems

When a slipping or undersized gear brings your build to a halt, you need a component you can trust. Engineers, robotics builders, and DIY machine makers who require consistent torque transfer and repeatable tooth engagement rely on module 3 spur gears machined from 45 steel — a medium-carbon steel known for its balance of hardness and machinability.

Each gear in this range is a flat spur gear cut to Module 3 (3Modul) geometry. The tooth count spans 10T through 30T, with corresponding outer diameters from 36 mm (≈1.42 in) to 96 mm (≈3.78 in). The bore and keyway dimensions vary by tooth count; see variant options for confirmed bore specifications. Gears are available individually or in multi-piece sets of up to 5 units.

Typical applications include open-frame CNC router drive trains, motorized conveyor reduction stages, DIY lathe headstock gear replacements, and modular robotics joint actuators where a module 3 spur gear pairing delivers the required gear ratio without backlash-prone belt systems.

⚙️ Compatibility: Meshes with any Module 3 (Mod 3) spur or helical gear of the same modulus. Confirm bore diameter and keyway against your shaft before ordering.

✅ Key Features of These Module 3 Spur Gears

🔩 45 Steel Construction

Medium-carbon 45 steel provides a tensile strength typically in the 600–800 MPa range, offering solid wear resistance for continuous-duty gear mesh without the cost of alloy steel.

📐 Module 3 Tooth Profile

Standardized Mod 3 geometry ensures direct interchangeability with any other Module 3 spur gear, simplifying ratio changes and replacement sourcing across your drivetrain.

📏 Wide Size Range: 10T–30T

Twenty-one tooth-count options from 10T (OD 36 mm) to 30T (OD 96 mm) let you dial in the exact gear ratio your application requires without custom machining.

🎯 Flat Gear Form Factor

The flat (non-helical) spur design produces no axial thrust load, making these gears straightforward to mount on parallel shafts with standard radial bearings.

📦 Multi-Piece Quantity Options

Order 1 to 5 pieces per variant to stock spares, build symmetric gear trains, or fulfill small-batch production runs — all priced per set at a consistent unit rate.

🔄 Direct Mesh Compatibility

Any two gears from this Module 3 range mesh correctly with each other, enabling you to build compound gear trains entirely from this product line for ratio flexibility.

📐 Technical Specifications — Module 3 Spur Gear

Modulus	3 (Module 3 / Mod 3)
Tooth Count Range	10T – 30T
Outer Diameter Range	36 mm – 96 mm (≈1.42 in – 3.78 in)
Material	45 Steel (medium-carbon steel)
Gear Type	Flat Spur Gear
Pressure Angle	20° (standard)
Bore Diameter	See variant options
Hub / Face Width	See variant options
Surface Finish	See variant options
Available Quantities	1 / 2 / 3 / 4 / 5 pcs per order

❓ Frequently Asked Questions

How do I choose the right tooth count for my gear ratio?

Divide the driven gear tooth count by the driver gear tooth count to get your reduction ratio. For example, pairing a 10T driver with a 30T driven gear gives a 3:1 reduction. All gears in this listing share Module 3, so any two tooth counts mesh correctly — simply select the combination that achieves your target ratio.

What is Module 3 and will it mesh with my existing gears?

Module (or Modulus) is the standardized metric tooth-size system. Module 3 means the pitch diameter equals 3 mm × tooth count. These gears mesh with any other Module 3 spur or helical gear regardless of brand, provided the pressure angle is also 20°. They are not compatible with Module 2, Module 4, or imperial diametral-pitch gears.

How strong are 45 steel gears and are they suitable for continuous-duty use?

45 steel has a typical tensile strength of 600–800 MPa and yield strength around 355–490 MPa in the normalized or quenched-and-tempered condition. This makes it well-suited for moderate-load, continuous-duty applications such as conveyor drives, CNC axis drives, and robotics joints. For very high shock loads or corrosive environments, consider upgrading to alloy steel or stainless variants.

Are these gears corrosion-resistant?

45 steel is a carbon steel and will oxidize if exposed to moisture without protection. For indoor or dry environments, the bare steel surface is adequate. For humid or outdoor use, apply a light machine oil or grease to the tooth faces and bore, or consider a zinc-plated or black-oxide variant if available. Contact us to confirm the surface finish on your selected variant.

What bore diameter and keyway size do these gears have?

Bore diameter and keyway dimensions vary by tooth count and outer diameter. Please check the variant detail page or contact us with your tooth count selection to confirm the bore size before ordering. We recommend verifying bore-to-shaft clearance to ensure a proper fit with your shaft diameter.

Can I order multiple pieces and will they be identical?

Yes. The QTY option lets you select 1 to 5 pieces of the same tooth-count variant in a single order. All pieces within a quantity set are identical in tooth count, outer diameter, and bore, making them suitable for symmetric gear trains, spare-parts stocking, or small-batch production builds.

Can these spur gears be used in a compound gear train?

Yes. Because all gears in this listing share Module 3 geometry, you can combine multiple tooth-count variants to build multi-stage compound gear trains. For example, a 10T → 30T first stage followed by a 10T → 25T second stage yields a 7.5:1 overall reduction. Ensure shaft center distances are calculated correctly for each meshing pair using the formula: center distance = (T1 + T2) × module / 2.

🛒 Select your Teeth-OD and QTY above, then add to cart.