Spur Gears Pinion Gear 1.5 Mod 45# Steel Teeth 20~30 Flat Gear Transmission Gear

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Spur Gears Pinion Gear 1.5 Mod 45# Steel Teeth 20~30 Flat Gear Transmission Gear

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By HomeDIYer®

Number Of Teeths: 20T

Bore Diameters: 6mm

Step Diameter & Packing Quantity: 25mm & 1 Pcs

Price:

$16.06 USD

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In stock (500 units), ready to be shipped

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1.5 Mod Spur Gears Pinion Gear — Reliable 45# Steel Flat Gear for Precision Transmission

When your DIY automation project, CNC build, or robotics assembly demands consistent torque transfer without slippage, the right spur gear makes all the difference. These 1.5 Module flat transmission gears are engineered for makers, hobbyists, and small workshop operators who need dependable mechanical components that fit standard shaft sizes without custom machining.

Each spur gear is machined from 45# carbon steel, offering a solid balance of hardness and machinability. The tooth count ranges from 20T to 30T, with bore diameters spanning 6 mm (0.24 in) to 15 mm (0.59 in) and step diameters of 25 mm (0.98 in), 30 mm (1.18 in), or 35 mm (1.38 in). The 1.5 Module pitch ensures compatibility with any mating gear of the same module standard.

These spur gears are well-suited for DIY gear reduction systems in 3D printer extruder drives, small conveyor belt mechanisms, and tabletop CNC router spindle assemblies — anywhere a compact, flat-profile pinion gear with a standard metric bore is required.

⚙️ Compatibility: Fits any mating gear with Module 1.5 (Mod 1.5) standard. Bore sizes 6 mm – 15 mm suit most standard metric motor shafts and lead screws.

✅ Key Features of These 1.5 Mod Spur Gears Pinion Gears

🔩 45# Carbon Steel Construction

Machined from 45# carbon steel for a reliable combination of surface hardness and core toughness, suitable for moderate-load transmission applications.

📐 Module 1.5 Standard Tooth Profile

1.5 Mod pitch ensures direct mesh compatibility with any Module 1.5 rack, pinion, or spur gear — no custom adaptation needed.

🎯 Wide Tooth Count Selection (20T – 30T)

Choose from 20, 24, 25, or 30 teeth to dial in your desired gear ratio for speed reduction or torque multiplication in your drivetrain.

🔄 Multiple Bore Diameter Options (6 – 15 mm)

Available in 6 mm, 6.35 mm, 7 mm, 8 mm, 10 mm, 12 mm, 14 mm, and 15 mm bore sizes to match standard metric and fractional motor shafts directly.

📦 Flexible Pack Quantities (1, 3, or 5 Pcs)

Order a single gear for prototyping or a multi-pack for production builds — step diameter and quantity are combined in one easy variant selector.

⚡ Flat Gear Profile for Compact Assemblies

The flat spur gear design keeps axial footprint minimal, making these pinion gears ideal for space-constrained gearboxes and inline transmission layouts.

📐 Technical Specifications — Spur Gear Pinion

Module (Mod)	1.5
Material	45# Carbon Steel
Number of Teeth	20T / 24T / 25T / 30T (see variant options)
Bore Diameter	6 mm / 6.35 mm / 7 mm / 8 mm / 10 mm / 12 mm / 14 mm / 15 mm (see variant options)
Step Diameter	25 mm / 30 mm / 35 mm (see variant options)
Gear Type	Spur Gear (Flat Pinion)
Tooth Profile	Standard involute, Module 1.5
Pressure Angle	20°
Surface Finish	See variant options
Pack Quantity	1 Pcs / 3 Pcs / 5 Pcs (see variant options)
Weight	See variant options

❓ Frequently Asked Questions

How do I choose the right number of teeth for my project?

The tooth count determines your gear ratio. Pair a lower-tooth pinion (e.g., 20T) with a larger driven gear for speed reduction and torque increase. Use a 30T pinion when you need a closer 1:1 ratio or moderate reduction. Calculate your ratio as: driven teeth ÷ pinion teeth = gear ratio.

Which bore diameter should I select for my motor shaft?

Match the bore diameter to your motor or lead screw shaft diameter. Common metric sizes are 6 mm, 8 mm, 10 mm, 12 mm, and 15 mm. The 6.35 mm option suits 1/4-inch imperial shafts. If your shaft is slightly undersized, a set screw or keyway can compensate — check your motor's datasheet for the exact shaft diameter before ordering.

What does the step diameter mean, and how does it affect installation?

The step diameter refers to the outer hub or shoulder diameter of the gear body. A 25 mm step suits compact gearbox housings, while 30 mm and 35 mm steps provide more bearing surface area for higher-load applications. Ensure your housing bore or bearing inner diameter matches the step diameter you select.

Are these gears compatible with Module 1.5 racks and other spur gears?

Yes. Any gear, rack, or pinion with a Module 1.5 (Mod 1.5) tooth profile and a 20° pressure angle will mesh correctly with these gears. Module is a universal metric standard — as long as the module number matches, the gears will engage properly regardless of tooth count.

How strong are 45# carbon steel gears, and are they corrosion-resistant?

45# carbon steel offers good tensile strength (typically 600–800 MPa) and is well-suited for moderate mechanical loads in dry or lightly lubricated environments. It is not inherently corrosion-resistant — for humid or outdoor applications, apply a light machine oil or grease coating. For highly corrosive environments, consider stainless steel alternatives.

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

Yes. These 1.5 Mod spur gears are commonly used in DIY CNC router spindle drives, 3D printer extruder gear trains, small robotic arm joints, and conveyor belt reduction stages. Select the tooth count and bore size that matches your motor shaft and desired gear ratio for a direct drop-in fit.

Should I buy 1, 3, or 5 pieces?

Order 1 piece for prototyping or a single-axis build. Choose 3 pieces if you are building a multi-axis system or want a spare. The 5-piece pack offers the best per-unit value for production runs, classroom kits, or projects requiring multiple identical gear stages.

🛒 Select your tooth count, bore diameter, and step diameter & quantity above, then add to cart.