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When your motion control project demands exact synchronization — whether you're building a CNC router, a 3D printer, or an automated conveyor — a mismatched or imprecise timing pulley can throw off your entire system. These XL timing belt pulleys are engineered for makers, hobbyists, and engineers who need reliable, repeatable power transmission without slippage or backlash.
Each pulley features an XL tooth profile (pitch: 5.08mm / 0.200 in) with a belt width of 11mm (approximately 0.43 in). Tooth counts range from 10T to 40T, and bore diameters span 4mm to 20mm (approximately 0.16 in to 0.79 in), with standard round bore and keyway variants available. The outer diameter scales with tooth count — typically ranging from approximately 16mm (0.63 in) for XL10 up to approximately 65mm (2.56 in) for XL40.
These XL synchronous pulleys are widely used in CNC machine X/Y axis drives, desktop 3D printer extruder and motion systems, small robotic arm joints requiring precise angular positioning, and DIY linear actuator builds where belt-driven motion is preferred over lead screws.
| Belt Profile | XL (Extra Light) |
|---|---|
| Tooth Pitch | 5.08mm (0.200 in) |
| Tooth Count (Types) | 10T, 12T, 14T, 15T, 16T, 17T, 18T, 19T, 20T, 22T, 24T, 25T, 30T, 32T, 35T, 36T, 40T |
| Belt Width | 11mm (0.43 in) |
| Bore Diameter | 4mm – 20mm (round bore); keyway variants available |
| Keyway Sizes | 3×1.4mm, 4×1.8mm, 5×2.3mm, 6×2.8mm (see variant options) |
| Outer Diameter | See variant options |
| Hub Width | 11mm |
| Material | See variant options |
| Finish | See variant options |
| Set Screw | Included on keyway variants |
The tooth count determines the pulley's pitch diameter and affects your drive ratio. A higher tooth count gives a larger pulley diameter, which can reduce belt speed or increase torque depending on the paired pulley. For most desktop CNC and 3D printer builds, XL15–XL20 are common choices for the motor pulley, paired with a larger driven pulley for reduction. Match your tooth count to your required belt speed and torque ratio.
A standard (round) bore pulley relies on a set screw or press fit to hold it on the shaft. A keyway bore includes a machined slot that accepts a key inserted between the shaft and pulley, providing a positive mechanical lock that resists rotational slipping under higher torque loads. If your application involves significant torque or reversing loads, a keyway variant is recommended.
Measure your motor or drive shaft diameter precisely with calipers. The bore must match the shaft diameter — a bore that is too large will cause runout and slippage, while one that is too small cannot be installed. For keyway variants, the bore notation (e.g., "14/5×2.3mm") means a 14mm bore with a 5mm wide × 2.3mm deep keyway slot.
Yes. These pulleys use the standard XL tooth profile with a 5.08mm (0.200 in) pitch, which is compatible with any standard XL-profile timing belt. Ensure your belt width is 11mm or narrower to match the 11mm hub width of these pulleys. Using a wider belt may cause the belt to ride over the pulley flanges.
The material specification varies by variant. Please refer to the variant options or contact us to confirm the material for your specific tooth count and bore combination. Common materials for this type of pulley include aluminum alloy and steel, each offering different weight and strength characteristics.
These pulleys are suitable for light-to-medium duty synchronous drive applications typical of desktop CNC machines, 3D printers, laser engravers, and small robotics. For high-torque applications, select a keyway variant to ensure positive shaft engagement. For very high-speed or industrial-duty applications, please contact us to confirm suitability for your specific load and speed requirements.
Yes, keyway variants include a set screw hole. A set screw is typically included or can be sourced as a standard metric fastener. The set screw works in conjunction with the keyway to provide secure, backlash-free shaft locking. Ensure you use the correct key stock matching the keyway dimensions specified in the variant name.
