5M BF-Type Timing Belt Pulley 20T/22T Synchronous Wheel For 15mm/20mm Width Belt

The tooth count determines the pitch diameter and, combined with your motor's RPM, the linear speed of your belt. A 20T pulley has a slightly smaller pitch diameter (~31.8 mm) than a 22T (~35.0 mm). If you are replacing an existing pulley, match the tooth count exactly. If you are designing a new drive, choose based on your desired speed ratio — more teeth means a larger diameter and higher belt speed at the same RPM.

Common NEMA 17 stepper motors use a 5 mm shaft, NEMA 23 motors typically use an 8 mm or 1/4-inch (6.35 mm) shaft, and NEMA 34 motors often use a 12 mm or 14 mm shaft. Match the bore diameter in the variant selector to your motor's shaft diameter. If your shaft has a flat or keyway, select the corresponding keyway bore option (e.g., 8mm(3×1.4mm) for an 8 mm shaft with a 3×1.4 mm keyway).

A round bore relies on a set screw to grip the shaft and is easier to install but can slip under high torque. A keyway bore uses a machined slot that mates with a key on the shaft, providing a positive mechanical lock that prevents rotational slippage — preferred for higher-torque or precision-indexing applications. Available keyway sizes are 3×1.4 mm, 4×1.8 mm, and 5×2.3 mm.

Yes, provided your belt is a standard 5M profile (5 mm pitch, trapezoidal tooth form). Confirm that your belt width matches the pulley variant you select — 15 mm belt width pulleys are not interchangeable with 20 mm belt width pulleys. The BF-type double flange helps retain the belt on the pulley face during operation.

These pulleys are suited for light-to-medium duty automation, CNC routing, 3D printing, and similar maker applications. For load capacity and maximum torque ratings specific to your setup, please contact us with your application details. Avoid shock loads or sustained overloads beyond the rated belt tension for the 5M profile.

Corrosion resistance depends on the material and finish of the specific variant. Please contact us to confirm the material and surface treatment before deploying in wet, humid, or chemically exposed environments. For indoor CNC and 3D printing use, standard variants are appropriate without additional treatment.

No. The pulley's flange spacing and tooth face width are sized for a specific belt width. Using a wider belt on a narrower pulley will cause the belt to ride over the flanges and derail. Always match the belt width to the pulley variant exactly.