4 Mod Spur Gear 10 to 60T Flat Gear Motor Transmission Gear 45# Steel Thick 40mm

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4 Mod Spur Gear 10 to 60T Flat Gear Motor Transmission Gear 45# Steel Thick 40mm

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By HomeDIYer®

Material: 45# Steel

Modulus: 4 Modulus

Teeth & Amount: 10 Teeth & 1 PCS

Price:

$70.71 USD

Stock:

In stock (500 units), ready to be shipped

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Module 4 Spur Gear — Precision 45# Steel Flat Gear for Motor Transmission Builds

When your drive system demands consistent torque transfer and dimensional accuracy, an undersized or poorly machined gear becomes the weakest link in the chain. Engineers, robotics builders, and DIY machine makers who work with Module 4 gear trains need a flat spur gear that holds tight tolerances across the full face width — without flex, wobble, or premature wear. This 45# steel spur gear is machined to Module 4 standards with a 40 mm (≈1.57 in) face width, giving you a robust, drop-in component for medium-duty transmission applications.

Each gear is cut from 45# carbon steel — a medium-carbon structural steel known for its balance of machinability, surface hardness after heat treatment, and tensile strength. The gear face width is 40 mm (1.57 in), with tooth counts ranging from 10T to 60T across 43 variants. Pitch diameter scales proportionally with tooth count at Module 4 (pitch diameter = teeth × 4 mm), so a 10T gear has a 40 mm pitch diameter and a 60T gear has a 240 mm pitch diameter. Bore diameter and keyway dimensions vary by variant — see variant options for confirmed bore specs.

Typical use cases include DIY CNC router axis drives, electric motor reduction stages in go-kart or e-bike transmissions, robotic arm joint actuators requiring a Module 4 gear mesh, and small industrial conveyor or indexing table drives where a wide-face spur gear provides stable load distribution.

⚙️ Compatibility: Meshes with any Module 4 spur or rack gear. Verify bore diameter and keyway against your shaft before ordering.

✅ Key Features of These Module 4 Spur Gears

🔩 45# Carbon Steel Construction

Machined from 45# medium-carbon steel for a reliable combination of machinability and load-bearing strength in gear train applications.

📐 Module 4 Standard — Wide Tooth Profile

Module 4 tooth geometry provides a wider, stronger tooth profile than finer modules, making these gears well-suited for moderate-torque drives and slower-speed reduction stages.

📏 40 mm Face Width for Stable Load Distribution

The 40 mm (1.57 in) face width spreads tooth load across a broad contact area, reducing localized stress and extending service life compared to narrower gears.

🔢 10T to 60T — 43 Tooth Count Options

Choose from 10 through 60 teeth (10–50T in single increments, plus 55T and 60T) to dial in your exact gear ratio without custom machining.

🎯 Flat Gear Profile — Direct Motor Shaft Mounting

The flat (non-hub-extended) gear body keeps axial stack height compact, ideal for space-constrained gearboxes and motor face-mount configurations.

🔄 Interchangeable with Standard Module 4 Gear Trains

Conforms to Module 4 tooth standards, allowing direct meshing with existing Module 4 spur gears, racks, and pinions in your drivetrain.

📐 Technical Specifications — Module 4 Spur Gear

Material	45# Carbon Steel
Module	4
Pressure Angle	20°
Face Width (Thickness)	40 mm (1.57 in)
Tooth Count Range	10T – 60T (43 variants)
Pitch Diameter	Teeth × 4 mm (e.g., 10T = 40 mm, 30T = 120 mm, 60T = 240 mm)
Bore Diameter	See variant options
Keyway	See variant options
Surface Finish	See variant options
Gear Type	Flat Spur Gear
Sold As	1 PCS per order

❓ Frequently Asked Questions

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

Divide the driver gear tooth count by the driven gear tooth count to get your reduction ratio. For example, a 10T pinion driving a 40T gear gives a 4:1 reduction. Select the tooth count that achieves your target ratio when paired with your existing pinion or driven gear. All variants in this listing are Module 4, so they mesh directly with any other Module 4 gear.

What is the pitch diameter for each tooth count?

For Module 4 gears, pitch diameter (mm) = number of teeth × 4. So a 10T gear has a 40 mm pitch diameter, a 20T gear has 80 mm, a 30T gear has 120 mm, and a 60T gear has 240 mm. Use this to calculate center distance between meshing gears: center distance = (pitch diameter of gear 1 + pitch diameter of gear 2) ÷ 2.

How strong is 45# steel for gear applications?

45# carbon steel (equivalent to AISI 1045) has a typical tensile strength of approximately 600–800 MPa in the normalized condition and can be heat-treated to higher hardness for increased wear resistance. It is a widely used gear material for moderate-torque, medium-speed applications such as motor reduction stages, conveyor drives, and robotic joints. For very high-torque or high-speed applications, consider whether additional surface hardening is needed.

Are these gears corrosion resistant?

45# carbon steel has limited inherent corrosion resistance. For outdoor, humid, or washdown environments, we recommend applying a rust-inhibiting oil or grease to the gear surfaces, or considering a surface coating such as black oxide or zinc plating. For corrosive environments, a stainless steel or engineering plastic gear may be more appropriate.

Will this gear fit my motor shaft? How do I confirm the bore size?

Bore diameter and keyway dimensions vary by tooth count variant. Please check the variant detail page or contact us to confirm the bore size for your selected tooth count before ordering. Measure your motor or gearbox shaft diameter accurately — a bore that is too small cannot be installed without machining, and a bore that is too large will cause runout and vibration.

Can I use this gear with a Module 4 rack for linear motion?

Yes. Module 4 spur gears mesh directly with Module 4 racks (linear gears). This is a common configuration for CNC router axes, 3D printer gantries, and linear actuator systems. Ensure the rack pitch matches Module 4 and that the gear is mounted at the correct center height above the rack pitch line for proper tooth engagement.

Is lubrication required, and what type is recommended?

Yes, lubrication is recommended for all steel spur gear meshes to reduce friction, heat, and wear. For enclosed gearboxes, an ISO VG 220 or VG 320 gear oil is typical. For open drives or periodic re-lubrication setups, a lithium-based grease or open-gear compound works well. Apply lubricant to the tooth flanks before initial operation and re-lubricate at regular service intervals based on your duty cycle.

🛒 Select your tooth count (Teeth & Amount) above, then add to cart.