0.5M 58T Spur Gears — Precision 45 Steel Pinion Gears for Reliable Transmission
When your motion-control build demands consistent torque transfer and tight mesh tolerances, undersized or poorly machined gears become the weakest link. Makers, robotics builders, and mechanical engineers who need repeatable, low-backlash power transmission rely on spur gears machined to exact module specifications — not approximations.
These 0.5 module 58-tooth spur gears are machined from 45 steel (medium-carbon steel), offering a balance of hardness and machinability suited to precision drive trains. The bore options range from 6 mm (~0.236 in) to 12 mm (~0.472 in), accommodating a variety of shaft diameters. Each gear features a standard involute tooth profile at Module 0.5, with an outer diameter of approximately 29.5 mm (~1.16 in) based on the formula OD = (T + 2) × M.
Typical use cases include DIY robotics gearboxes requiring compact 0.5M spur gear sets, CNC machine axis drives using 58-tooth steel pinion gears, and small automation mechanisms where metal spur transmission gears replace plastic counterparts for extended service life.
⚙️ Compatible with all standard Module 0.5 gear systems. Select your bore size (6 / 8 / 10 / 12 mm) to match your shaft diameter. Pair with any M0.5 rack, pinion, or mating gear for correct mesh.
✅ Key Features of These 0.5M 58T Steel Spur Gears
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45 Steel Construction
Machined from medium-carbon 45 steel for a reliable combination of surface hardness and core toughness — suitable for continuous-duty drive applications.
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Standard Module 0.5 Involute Profile
Full-depth involute tooth form ensures smooth mesh with any M0.5 mating gear, rack, or pinion without custom modification.
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58-Tooth Count for Defined Gear Ratios
58T enables precise ratio calculations when paired with common pinion tooth counts (e.g., 58:29 = 2:1 reduction), simplifying gearbox design.
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Multiple Bore Options (6–12 mm)
Available with 6 mm, 8 mm, 10 mm, or 12 mm center bores to fit standard motor and shaft diameters without additional machining in most setups.
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Flexible Pack Quantities (1–30 pcs)
Order from a single gear for prototyping up to 30-piece packs for production runs or spares inventory — all at consistent per-unit quality.
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Broad Application Compatibility
Suited for robotics, CNC drives, conveyor mechanisms, and small automation systems where metal spur transmission gears are required over plastic alternatives.
📐 Technical Specifications — 0.5M Spur Gears
| Module |
0.5 |
| Number of Teeth |
58T |
| Tooth Profile |
Standard Involute |
| Material |
45 Steel (Medium-Carbon Steel) |
| Outer Diameter (OD) |
Approx. 29.5 mm (1.16 in) |
| Pitch Diameter (PD) |
29 mm (1.14 in) |
| Bore Diameter |
6 mm / 8 mm / 10 mm / 12 mm (See variant options) |
| Face Width |
See variant options |
| Pressure Angle |
20° |
| Finish / Surface Treatment |
See variant options |
| Pack Quantity |
1 / 5 / 10 / 15 / 20 / 25 / 30 pcs (See variant options) |
| Application |
Robotics, CNC, Automation, DIY Drive Systems |
❓ Frequently Asked Questions
How do I choose the right bore size for my shaft?
Measure your motor or drive shaft diameter with calipers. Select the bore option that matches: 6 mm, 8 mm, 10 mm, or 12 mm. If your shaft falls between sizes, the smaller bore can be reamed or bored out by a machinist to an exact fit. Do not select a bore larger than your shaft diameter.
What gear ratio can I achieve with a 58T spur gear?
Gear ratio = driven teeth ÷ driving teeth. Pairing this 58T gear as the driven gear with a 29T pinion gives a 2:1 reduction. With a 14T pinion you get approximately 4.14:1. Because the module is 0.5, any M0.5 mating gear will mesh correctly regardless of tooth count.
Is 45 steel strong enough for my application?
45 steel (equivalent to SAE 1045) has a tensile strength of approximately 600–800 MPa in the normalized condition. It is well-suited for moderate-load, continuous-duty drives such as robotics joints, CNC axis drives, and small conveyor systems. For very high-shock or high-speed applications, consider whether a heat-treated or alloy steel variant is more appropriate for your load requirements.
Will these gears rust or corrode?
45 steel is a carbon steel and will oxidize if exposed to moisture without protection. For indoor or dry environments, a light machine oil coating is sufficient. For humid or outdoor-adjacent environments, apply a corrosion-inhibiting grease or consider a zinc-plated alternative. The surface finish of each variant is listed in the variant options.
Are these compatible with Module 0.5 racks and other M0.5 gears?
Yes. All Module 0.5 gears with a 20° pressure angle share the same involute tooth geometry and will mesh correctly with each other, including M0.5 racks, pinions, and idler gears from any manufacturer. Verify the pressure angle (20°) matches your existing gear train before ordering.
How many gears should I order for a project?
For prototyping, a single-piece (1 pc) order lets you verify fit and mesh before committing. For small production runs or builds with multiple identical axes, the 5- or 10-piece packs offer a lower per-unit cost. The 15–30 piece packs are suited for batch builds, classroom kits, or maintaining a spares inventory.
Can I use these gears with plastic mating gears?
Yes, but with a caveat: steel gears will wear plastic mating gears significantly faster than a steel-on-steel pairing. If your existing gear train uses plastic gears, replacing only one gear with steel may accelerate wear on the plastic counterpart. For longevity, pair steel with steel throughout the mesh.
🛒 Select your Teeth–Bore size and quantity above, then add to cart.
