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When your CNC router, robotics platform, or custom automation rig demands reliable belt drive performance, a poorly fitted pulley creates slip, vibration, and premature belt wear. Engineers, makers, and DIY builders who work with 6mm round polyurethane belts need a pulley that holds the belt firmly in the groove without wobble or misalignment. These V grooved aluminum pulleys are machined to deliver consistent, low-friction rotation across a wide range of shaft sizes and wheel diameters.
Each pulley is machined from aluminum alloy, offering a lightweight yet rigid construction. The V-groove profile is sized specifically for 6mm width PU round belts. Outer diameters span from 20mm (~0.79 in) to 100mm (~3.94 in), and bore diameters range from 4mm to 25mm, covering the most common shaft sizes used in maker and industrial applications. A set screw secures the pulley to the shaft for positive, slip-free engagement.
Typical use cases include CNC machine axis drives where smooth belt tracking is critical, 3D printer and laser cutter belt systems requiring precise OD-to-bore ratios, and custom conveyor or pick-and-place automation builds where a lightweight aluminum V groove pulley for round belt reduces rotational inertia and improves response time.
| Material | Aluminum Alloy |
|---|---|
| Belt Type Compatibility | 6mm Width PU Round Belt |
| Groove Type | V-Groove |
| Outer Diameter (OD) | 20 / 30 / 40 / 60 / 80 / 100mm — See variant options |
| Bore Diameter | 4 / 5 / 6 / 7 / 8 / 10 / 11 / 12 / 14 / 15 / 16 / 17 / 18 / 19 / 20 / 22 / 24 / 25mm — See variant options |
| Shaft Fixation | Set Screw |
| Finish | Natural Aluminum (uncoated) |
| Weight | See variant options |
| Quantity per Order | 1 Piece |
These pulleys are machined with a V-groove sized for 6mm diameter PU (polyurethane) round belts. They are not intended for flat belts, toothed timing belts, or belts with a different cross-section diameter. Using the correct belt profile ensures the belt seats fully in the groove and tracks without slipping sideways.
Measure your motor or idler shaft diameter with a caliper before ordering. The bore diameter of the pulley must match your shaft diameter. Available bore sizes range from 4mm to 25mm. If your shaft is metric, select the exact matching bore. The set screw allows fine clamping adjustment, but the bore must be the correct nominal size for a proper fit.
Drive ratio is determined by the ratio of the driver pulley OD to the driven pulley OD. For example, a 20mm driver paired with a 60mm driven pulley gives a 3:1 reduction. Choose your OD combination based on the speed and torque requirements of your application. Six OD options — 20, 30, 40, 60, 80, and 100mm — are available to cover a wide range of drive ratio configurations.
Yes, a set screw is included with each pulley. Set screws on pulleys of this type typically require a hex (Allen) key for tightening. The specific hex key size depends on the set screw diameter, which varies by pulley size. A standard metric hex key set will cover all variants in this range.
Yes. These pulleys can function as both driver/driven pulleys (fixed to a shaft via set screw) and as idler pulleys when mounted on a bearing-supported shaft or axle. For idler use, ensure the bore fits your idler shaft and that the shaft is free to rotate or that a bearing is used between the shaft and pulley bore as needed by your design.
Aluminum alloy naturally forms a thin oxide layer that provides moderate corrosion resistance in typical indoor environments. These pulleys are suitable for dry or lightly humid workshop and lab conditions. For outdoor or high-humidity environments, consider applying a light coating of machine oil or using an anodized variant if available. Avoid prolonged exposure to salt spray or aggressive chemicals.
Yes, provided your machine uses 6mm PU round belts and the shaft diameter matches one of the available bore sizes. Many DIY 3D printers, laser cutters, and CNC routers use round belt drive systems. Verify the OD fits your belt path geometry and that the bore matches your motor shaft before ordering.
Exact load ratings depend on the specific OD, bore, and operating speed of your application. Aluminum alloy pulleys of this type are suitable for light-to-medium duty drive applications typical of CNC machines, robotics, and automation equipment. For heavy industrial loads or high-speed continuous operation, consult your system's belt tension and torque requirements against the pulley's cross-section to confirm suitability.
