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When your CNC router, robotic arm, or RC drivetrain demands consistent torque transfer without backlash, a poorly matched gear becomes the weakest link in your build. These 0.5 module pinion spur gears are engineered for makers, automation engineers, and hobbyists who need reliable, repeatable motion in compact drive systems.
Each gear is machined from 45# carbon steel, offering a solid balance of hardness and machinability. The step-bore design accommodates a range of shaft diameters from 4 mm to 15 mm (approximately 0.16 in to 0.59 in), with tooth counts spanning 20 T to 60 T. Overall gear outer diameters range from approximately 11 mm to 31 mm (0.43 in to 1.22 in) depending on tooth count, with face widths of 3 mm or 5 mm depending on the selected variant.
Typical use cases include 0.5 mod gear trains in desktop CNC machines, small robotic joint actuators, 3D printer extruder drives, and RC car transmission assemblies requiring a compact pinion-to-spur mesh. The step-bore configuration also makes these gears well-suited for shaft-to-gear retrofits where a set-screw or press-fit is needed on a specific shaft diameter.
Machined from 45# medium-carbon steel for a reliable combination of surface hardness and core toughness, suitable for moderate-load gear train applications.
Conforms to the 0.5 module (Mod 0.5) gear standard, ensuring direct mesh compatibility with any other Mod 0.5 spur gear, rack, or pinion in your drivetrain.
Available in 25 tooth-count options from 20 T to 60 T, giving you precise gear ratio flexibility for speed reduction or torque multiplication in compact assemblies.
The stepped bore accommodates shaft diameters from 4 mm to 15 mm (including 6.35 mm / 1/4 in and keyed bore options), reducing the need for custom machining when retrofitting existing shafts.
Order as a single piece for prototyping or as a 3-pack for production builds and spares inventory — both options available across all tooth count and bore combinations.
Face widths of 3 mm or 5 mm (depending on variant) keep axial footprint minimal, making these gears ideal for space-constrained enclosures and layered gear stacks.
| Module | 0.5 |
|---|---|
| Material | 45# Carbon Steel |
| Tooth Count Range | 20 T – 60 T (25 options) |
| Bore Diameter Options | 4 mm, 5 mm, 6 mm, 6.35 mm, 8 mm, 10 mm, 12 mm, 14 mm, 15 mm; keyed bores: 8/3×1.4 mm, 10/3×1.4 mm, 10/4×1.8 mm, 12/4×1.8 mm, 14/5×2.3 mm, 15/5×2.3 mm |
| Face Width | 3 mm or 5 mm (see variant options) |
| Pressure Angle | See variant options |
| Gear Type | Spur (straight tooth) |
| Finish | See variant options |
| Package Quantity | 1 Pcs or 3 Pcs |
The tooth count determines your gear ratio. Divide the driven gear's tooth count by the driving gear's tooth count to get the ratio. For example, a 20 T pinion driving a 60 T spur gives a 3:1 reduction — tripling torque while reducing speed by the same factor. Match your required ratio to the available tooth counts in this listing.
Select the bore diameter that matches your motor or drive shaft diameter. Standard round bores (4–15 mm) suit plain shafts secured with a set screw or adhesive. Keyed bore options (e.g., 8/3×1.4 mm) include a keyway slot for positive torque transmission — the format is bore diameter / key width × key depth. Measure your shaft with calipers before ordering.
Yes. Module 0.5 is an internationally standardized gear specification. These gears will mesh correctly with any other Mod 0.5 spur gear, rack, or pinion regardless of brand, provided the pressure angle also matches (typically 20°). Always confirm the pressure angle of your mating gear before assembling.
45# carbon steel (equivalent to AISI 1045) offers a tensile strength of approximately 600–700 MPa in the normalized condition. These gears are suitable for light-to-moderate loads typical of CNC routers, robotic joints, and RC drivetrains. For heavy industrial loads or continuous high-torque applications, consider hardened or alloy steel alternatives.
45# carbon steel has limited inherent corrosion resistance. For indoor or dry environments, the as-machined surface is generally adequate. For humid or outdoor use, apply a light machine oil or grease to the gear teeth and bore, or consider a surface treatment such as zinc plating or black oxide coating after purchase.
Yes. The 0.5 mod standard and compact face widths make these gears well-suited for desktop CNC machines, 3D printer extruder gear trains, and small robotic actuators. Verify that the bore diameter matches your stepper motor shaft (commonly 5 mm or 6.35 mm / 1/4 in) and that the tooth count gives you the desired feed rate or extrusion ratio.
Face width affects load capacity and axial stability. The 5 mm face width variants (e.g., 30 T thick 5 mm, 40 T thick 5 mm) provide a larger contact area, distributing load over more tooth surface and improving torque capacity. The 3 mm variants are lighter and more compact, ideal for space-constrained builds where load is moderate.
