0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel
0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel
0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel
0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel
0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel
0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel
0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel
0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel
0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel
Roll over image to zoom in Click on image to zoom
0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel

0.5 Mod 28 Teeth Spur Gear Bore 4/5/6mm Motor Gears Transmission Gears 45# Steel

HomeDIYer
No reviews

By HomeDIYer®

Price:
$10.58 USD
Stock:
In stock (500 units), ready to be shipped

Payment & Security

Ach Direct Debit Amazon American Express Apple Pay Bancontact BLIK Diners Club Discover EPS Google Pay iDEAL Wero JCB Maestro Mastercard Multibanco MobilePay PayPal Przelewy24 Shop Pay Twint Union Pay USDC Visa

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.

Limited Offer — Spend More, Save More
Spend $55+
Save $5
Spend $100+
Save $10
Spend $200+
Save $25
✅ Discount applied automatically at checkout 🚚 Free shipping on orders over $89
HomeDIYer DIY Expert Support

DIY Expert Support

Get fitment advice & recommendations

Mon–Fri  8:30 AM – 8:00 PM
WhatsApp
24-Hour Fast Ship
Arrives in 3–14 Days
Worldwide Shipping
30-Day Returns
1 tree planted with every purchase

Description

0.5 Mod 28-Tooth Spur Gear — Precision Motor Drive for DIY Automation

When your motor drive slips, your encoder skips, or your robot arm loses position, the culprit is often an undersized or poorly machined gear. Hobbyists, makers, and small-workshop engineers who build precise motion systems need a 0.5 mod 28-tooth spur gear they can trust to mesh cleanly and hold torque without backlash creep.

Each gear is machined from 45# carbon steel — a medium-carbon alloy known for its balance of hardness and toughness — and cut to a 0.5 module (pitch) with 28 teeth. The bore options span 4 mm (~0.157 in), 5 mm (~0.197 in), and 6 mm (~0.236 in), covering the most common motor shaft diameters in this size class. Overall outer diameter is approximately 15 mm (~0.59 in), with a face width typically in the 5–8 mm range depending on the specific variant.

These 0.5 mod spur gears are well-suited for small DC motor gearboxes in desktop CNC machines, stepper-driven pen plotters, lightweight robotic joints, and educational automation kits where compact gear trains and repeatable positioning are essential.

⚙️ Compatibility: Fits standard 0.5 module gear systems. Mates with any 0.5 mod rack, pinion, or mating gear. Bore sizes 4 mm, 5 mm, and 6 mm match common N20, TT, and small NEMA motor shafts. Verify shaft diameter before ordering.

✅ Key Features of These 0.5 Mod 28-Tooth Spur Gears

🔩
45# Carbon Steel Construction

Machined from 45# medium-carbon steel for a reliable combination of surface hardness and core toughness — resisting wear under repeated cyclic loading in motor drive applications.

📐
0.5 Module, 28 Teeth

Standard 0.5 mod pitch ensures direct interchangeability with any 0.5 module rack or mating gear. 28 teeth provide a practical gear ratio reference point for speed and torque calculations.

🎯
Three Bore Options: 4 / 5 / 6 mm

Select the bore that matches your motor shaft — 4 mm, 5 mm, or 6 mm — for a direct press or keyed fit without custom machining. Covers the most common small motor shaft diameters.

📦
Flexible Pack Quantities

Available in packs of 1, 2, 3, 4, 5, 8, or 10 pieces. Stock spares for prototyping, order multiples for production runs, or mix bore sizes across packs to suit your build.

🔄
Spur Gear Profile for Low-Noise Parallel Drives

Straight-cut spur tooth profile transmits power efficiently between parallel shafts with minimal axial thrust — ideal for compact gearboxes where helical gears would add unwanted side-load.

🛠️
Ready for Shaft Keyway or Set-Screw Mounting

Smooth bore accepts a set screw or can be broached for a keyway. Compatible with standard motor shaft retention methods used in DIY robotics and automation projects.

📐 Technical Specifications — 0.5 Mod Spur Gear

Module (Pitch) 0.5 mod
Number of Teeth 28 T
Bore Diameter 4 mm / 5 mm / 6 mm (see variant options)
Outer Diameter (OD) Approx. 15 mm (~0.59 in)
Pitch Diameter 14 mm (0.5 mod × 28 T)
Face Width See variant options
Pressure Angle 20°
Material 45# Carbon Steel
Finish See variant options
Gear Type Spur Gear (straight-cut)
Shaft Fit Smooth bore; set-screw or keyway compatible
Pack Quantity 1 / 2 / 3 / 4 / 5 / 8 / 10 pcs (see variant options)
Weight (per piece) See variant options

❓ Frequently Asked Questions

How do I choose the right bore size for my motor shaft?

Measure your motor shaft diameter with a caliper. Common small motor shafts run 4 mm (N20-style motors), 5 mm (many TT gear motors), or 6 mm (larger DC and stepper motors). Select the bore that matches your shaft for a direct fit. If your shaft is slightly undersized, a set screw can compensate; if oversized, the bore cannot be reduced — choose the correct size at order time.

Will this gear mesh with my existing 0.5 mod rack or pinion?

Yes. Any gear or rack with a 0.5 module pitch and a matching 20° pressure angle will mesh correctly with this gear. Confirm both the module and pressure angle of your mating component before assembling. Mixing modules (e.g., 0.5 mod with 0.8 mod) will result in incorrect meshing and rapid wear.

How strong is 45# steel for motor drive applications?

45# carbon steel (roughly equivalent to AISI 1045) offers a tensile strength typically in the 600–800 MPa range in its normalized state, making it suitable for light-to-medium duty motor drives, robotics joints, and automation mechanisms. For high-shock or continuous heavy-load applications, consider heat-treated or alloy steel gears. For typical DIY and educational automation loads, 45# steel performs reliably.

Is this gear corrosion-resistant for outdoor or humid environments?

45# carbon steel is not inherently corrosion-resistant. For outdoor, humid, or washdown environments, apply a light machine oil or grease coating to the gear teeth and bore, or consider stainless steel alternatives. For indoor, dry automation and robotics applications, bare or lightly oiled 45# steel performs well without additional treatment.

Can I use multiple gears together to build a gear train?

Yes. These 0.5 mod 28T gears can be combined with other 0.5 mod gears of different tooth counts to create compound gear trains for speed reduction or torque multiplication. Multi-pack options (2, 3, 4, 5, 8, or 10 pcs) make it cost-effective to stock the quantity you need for a full gear stage or to keep spares on hand during prototyping.

What is the gear ratio if I pair this 28T gear with a different tooth count?

Gear ratio = driven teeth ÷ driving teeth. For example, pairing this 28T gear (driver) with a 56T gear (driven) gives a 2:1 reduction — halving speed and doubling torque. Pairing it with a 14T gear gives a 1:2 increase in speed. Use this formula to design the ratio you need for your specific motor and load combination.

Do I need any special tools to install this gear on a motor shaft?

For a set-screw mount, you need only a hex key (Allen wrench) matching the set screw size. For a press fit, a small arbor press or bench vise with protective jaws is recommended to avoid damaging the gear teeth. If you plan to broach a keyway, a broaching kit and arbor press are required. No specialized gear installation tools are needed for standard set-screw mounting.

🛒 Select your Size (Bore) and Packing Quantity above, then add to cart.

You may also like

Recently viewed