45# Steel 4Mod 10T-80T Spur Gears Thickness 35mm Motor Pinion Transmission Gear

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45# Steel 4Mod 10T-80T Spur Gears Thickness 35mm Motor Pinion Transmission Gear

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Number of tooth: 4M 10T

Amount: 1Pcs

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$26.86 USD

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In stock (500 units), ready to be shipped

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4Mod Spur Gears in 45# Steel — Reliable Pinion Transmission for DIY Automation

When your CNC router, robotic arm, or motorized DIY project demands consistent torque transfer without slippage, the right spur gear makes all the difference. Makers, hobbyists, and small-workshop engineers who need a wide tooth-count selection in a single standardized module will find these 4Mod spur gears a dependable foundation for their drivetrain builds.

Each gear is machined from 45# medium-carbon steel, offering a solid balance of hardness and machinability. The module is 4M (4mm pitch diameter per tooth), with a uniform face width of 35mm (~1.38 in). Tooth counts span from 10T to 80T, giving pitch diameters that range from approximately 40mm (~1.57 in) for the 10T up to 320mm (~12.6 in) for the 80T variant.

Typical use cases include motor pinion assemblies in CNC gantry systems, gear-reduction stages in conveyor and indexing tables, and custom rotary actuators in educational robotics labs — all scenarios where a standard 4Mod tooth profile ensures interchangeable meshing with off-the-shelf mating gears.

⚙️ Compatibility: Meshes with any standard Module 4 (4M) spur or helical gear. Bore diameter varies by tooth count — confirm bore size against your shaft before ordering.

✅ Key Features of These 4Mod Spur Gears

🔩45# Medium-Carbon Steel Construction — Machined from 45# steel for a reliable combination of surface hardness and core toughness suited to moderate-to-heavy load applications.
📐Module 4 (4M) Tooth Profile — Standardized 4M module ensures direct interchangeability with any Module 4 mating gear, rack, or pinion in your drivetrain.
📏35mm Face Width — A generous 35mm (~1.38 in) tooth face distributes load evenly across the gear width, reducing localized wear under sustained operation.
🔢Wide Tooth-Count Range (10T–80T) — Sixty tooth-count options from 10T to 80T let you dial in the exact gear ratio your project requires without custom machining.
⚖️Consistent Dimensional Accuracy — Each gear is turned and hobbed to maintain pitch-circle concentricity, keeping backlash predictable and motion smooth across the full speed range.
🛠️Versatile Application Fit — Suitable for motor pinion stages, reduction gearboxes, conveyor drives, and rotary indexing fixtures in CNC, robotics, and automation projects.

📐 Technical Specifications — 4Mod Spur Gears

Material	45# Medium-Carbon Steel
Module	4M (Module 4)
Face Width (Thickness)	35mm (~1.38 in)
Tooth Count Range	10T – 80T (see variant options)
Pitch Diameter Range	40mm – 320mm (varies by tooth count)
Pressure Angle	20° (standard)
Bore Diameter	See variant options
Surface Finish	See variant options
Gear Type	External Spur Gear
Tooth Profile Standard	Module 4 (ISO/DIN compatible)
Quantity per Order	1 Piece

❓ Frequently Asked Questions

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

Select your tooth count based on the gear ratio you need. Divide the driven gear teeth by the driver gear teeth to get the ratio. For example, pairing a 20T pinion with a 60T gear gives a 3:1 reduction. Use smaller tooth counts (10T–20T) for high-speed pinion stages and larger counts (40T–80T) for the driven wheel in reduction stages.

What shaft diameter does this gear fit?

The bore diameter varies by tooth count variant. Please check the variant detail or contact us to confirm the bore size before ordering. Most variants can be re-bored or keyed by a local machine shop if the standard bore does not match your shaft.

Will this gear mesh with my existing Module 4 gears?

Yes. Any gear with a Module 4 (4M) tooth profile and a 20° pressure angle will mesh correctly with these gears, regardless of brand. Confirm that your existing gear is labeled "M4" or "Module 4" before ordering.

How strong is 45# steel for gear applications?

45# steel (equivalent to AISI 1045) has a tensile strength of approximately 600–800 MPa in its normalized state and can be heat-treated to increase surface hardness. It is widely used for moderate-load power transmission gears in industrial and DIY machinery where a balance of machinability and strength is required.

Is this gear corrosion-resistant?

45# carbon steel is not inherently corrosion-resistant. For outdoor or humid environments, apply a light machine oil or grease coating during storage and operation. If corrosion resistance is critical, apply a rust-inhibiting surface treatment after installation.

Can I use these gears in a CNC router or 3D printer build?

Yes. These 4Mod spur gears are commonly used in CNC gantry drives, rotary axis assemblies, and extruder gear stages where a robust metal gear is preferred over plastic. Verify that your motor pinion is also Module 4 to ensure proper meshing and backlash control.

What is the size difference between the 10T and 80T variants?

The pitch diameter equals the module multiplied by the tooth count. For Module 4: the 10T gear has a pitch diameter of 40mm (~1.57 in), while the 80T gear has a pitch diameter of 320mm (~12.6 in). All variants share the same 35mm face width and 4M tooth profile.

🛒 Select your tooth count (Number of tooth) above, then add to cart.

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These o rings are a great for my ear tunnels

These o rings are a great for my ear tunnels, always loosing one here and there, I always have a new ones in the drawer. Being silicone, don't have any reactions compared to standard rubber ones I purchased at hardware stores, plus much less expensive. Purchased 16mm I'd to use on 19mm tunnels, and stay on great, might be able to get away with 17mm rings, but really happy with my choice.

Will never order from these folks again

I waited a long time and that’s all I received was the eyebolt with no threaded rod attached to it

Perfect they are really made well and I used them for my car

Perfect they are really made well and I used them for my car. The only thing I had a great for us. It took three weeks to get here. So shipping was slow.

did not include wing nuts

Hi Scott, thank you for your feedback. We're sorry for any inconvenience caused. Please get in touch with us directly, and we'll assist you. Thanks for shopping with HomeDIYer!

Haven't received the order yet! It's been over

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45# Steel 4Mod 10T-80T Spur Gears Thickness 35mm Motor Pinion Transmission Gear

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DIY Expert Support

Description

4Mod Spur Gears in 45# Steel — Reliable Pinion Transmission for DIY Automation

✅ Key Features of These 4Mod Spur Gears

📐 Technical Specifications — 4Mod Spur Gears

❓ Frequently Asked Questions

45# Steel 4Mod 10T-80T Spur Gears Thickness 35mm Motor Pinion Transmission Gear

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