L Timing Belt Pulleys Synchronous Wheel 13mm Width 10 - 20 Teeth 6mm-28mm Bore

The tooth count determines the pulley's pitch diameter and, combined with your driven pulley's tooth count, sets the drive ratio. For a 1:1 ratio use identical tooth counts on both pulleys. To increase output speed, use a smaller tooth count on the motor pulley; to increase torque, use a larger tooth count. Common starting points for light CNC and 3D printer builds are 16T–20T on the motor shaft.

Plain bore pulleys have a smooth cylindrical hole and rely on a set screw or press fit for retention — suitable for lighter loads and lower torques. Keyway bore variants (indicated by K3, K4, K5, K6, or K8 in the bore option) include a precision-machined keyway slot that accepts a standard key, providing positive torque transmission and preventing rotation under high or reversing loads. The number after K indicates the keyway width in mm (e.g., K5 = 5 mm keyway).

Yes — provided your belt is a standard L-pitch (3/8 in / 9.525 mm pitch) belt with a 13 mm or narrower usable width. These pulleys are machined to the L-pitch tooth profile, so they engage correctly with any conforming L-type belt. If your belt is wider than 13 mm or uses a different pitch (e.g., T5, T10, HTD 3M/5M), these pulleys will not be compatible.

Use a digital caliper to measure the shaft outer diameter at the mounting location. Select the bore size that matches your shaft diameter exactly for a plain bore, or choose the keyway bore option whose bore diameter matches your shaft and whose keyway width matches your key stock. For imperial shafts, note that 6.35 mm bore corresponds to 1/4 in (0.250 in) shaft diameter.

Plain bore aluminum variants are well-suited for light-duty CNC routers, 3D printers, and small conveyor systems operating at moderate speeds and torques. For higher-torque or reversing-load applications — such as indexing tables or servo-driven axes — select a keyway bore variant, which provides a more secure shaft connection. If your application involves continuous heavy loads, contact us to confirm suitability before ordering.

Flange configuration varies by variant — please refer to the variant options or product images for the specific pulley you are ordering. Many L-pitch pulleys in this range include flanges on one or both sides to guide the belt and prevent lateral walk-off during operation. If flange presence is critical for your design, contact us to confirm before purchasing.

Yes. Select the bore size that matches your motor's output shaft diameter. For NEMA 17 stepper motors the typical shaft is 5 mm — note that 5 mm is not listed; the closest plain bore is 6 mm, which would require a shaft adapter or bushing. For NEMA 23 steppers with 6.35 mm (1/4 in) shafts, the 6.35 mm plain bore variant is a direct fit. For servo motors with larger shafts, choose the appropriate bore from the variant list.