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When your motion-control project demands consistent belt tracking and minimal slippage, a poorly matched pulley becomes the weakest link in the entire drive train. These V groove aluminum pulleys are engineered for hobbyists, robotics builders, and small-machine designers who need a reliable, dimensionally accurate sheave that locks a 5mm round belt firmly in its groove without wandering or jumping under load.
Each pulley is machined from aluminum alloy, offering a lightweight yet rigid body with a natural resistance to corrosion. The V-profile groove is sized specifically for 5mm-width round belts, with a consistent 5mm bore through the hub. Outer diameters span three families — 20mm (~0.79 in), 30mm (~1.18 in), and 40mm (~1.57 in) — while groove widths range from 4mm to 16mm across variants, letting you match the pulley geometry to your exact belt and shaft configuration.
Typical applications include DIY belt-drive linear actuators, desktop CNC and 3D printer axis drives, small conveyor systems, and light-duty robotic arm joints where a compact round-belt pulley with a 5mm bore is required. The aluminum construction also makes these pulleys a practical choice for camera slider rigs and educational automation kits where weight savings matter.
The groove geometry is machined to seat a 5mm round belt securely, maintaining consistent belt tracking and reducing lateral drift during operation.
Aluminum construction keeps rotating mass low, reducing inertia in high-cycle applications such as 3D printer axes and robotic joints.
Choose the outer diameter that matches your required speed ratio. Groove widths from 4mm to 16mm give additional flexibility for different belt lengths and wrap angles.
The 5mm bore fits widely available motor shafts and lead-screw diameters, simplifying integration into existing drive assemblies without custom machining.
Aluminum's natural oxide layer provides adequate corrosion resistance for indoor and light-industrial environments, keeping the pulley serviceable over extended use cycles.
Each listing unit is a single pulley, allowing you to order exactly the OD and groove-width combination your project requires without paying for unwanted extras.
| Material | Aluminum alloy |
|---|---|
| Groove Profile | V-groove (round belt) |
| Belt Width Compatibility | 5mm round belt |
| Bore Diameter | 5mm |
| Outer Diameter (OD) | 20mm / 30mm / 40mm (see variant options) |
| Groove Width | 4mm – 16mm (see variant options) |
| Hub / Body Thickness | 5mm |
| Surface Finish | See variant options |
| Weight (per piece) | See variant options |
| Quantity per Unit | 1 piece |
These pulleys are designed exclusively for 5mm round belts (also called O-ring drive belts). The V-profile groove is sized to seat a 5mm-diameter round cross-section belt. Flat belts, V-belts with trapezoidal profiles, or timing belts are not compatible with this groove geometry.
The OD determines your drive ratio when paired with a second pulley. A larger OD on the driven pulley reduces output speed and increases torque; a smaller OD does the opposite. Measure the center-to-center shaft distance and your required belt length, then use a pulley-ratio calculator to confirm the OD combination before ordering. Available ODs are 20mm, 30mm, and 40mm.
The groove width affects how much of the belt sits inside the groove and influences belt retention. For a standard 5mm round belt, groove widths in the 5–8mm range typically provide good retention. Wider grooves (10–16mm) may be used when the belt needs more lateral clearance or when the pulley is used as an idler. Check your belt supplier's recommendation for the specific belt diameter you are using.
The bore is 5mm in diameter. If your motor or drive shaft is exactly 5mm, the pulley should slide on with a light press or clearance fit depending on machining tolerance. For a secure connection, a set screw, retaining pin, or shaft collar is recommended. If your shaft is a different diameter, a bore adapter or custom machining would be required.
Aluminum alloy provides a good strength-to-weight ratio suitable for light-to-medium duty continuous operation such as 3D printer axes, camera sliders, and small conveyor drives. For heavy-load or high-shock applications, verify that the aluminum grade and wall thickness meet your torque and radial load requirements. Contact us to confirm specifications if you have specific load data.
Aluminum naturally forms a thin oxide layer that provides adequate corrosion resistance for indoor and light-industrial environments. For prolonged exposure to moisture, salt spray, or aggressive chemicals, an additional anodized or coated finish would offer better protection. These pulleys are not rated for marine or outdoor weathering applications without additional surface treatment.
Yes. V groove pulleys are commonly used as idlers to guide and tension a round belt. When used as an idler, the bore can be fitted with a bearing (5mm ID bearing) to allow free rotation on a fixed shaft. Ensure the bearing outer diameter matches the bore, or use a bearing with a 5mm inner race and press it into a suitable housing.
