XL10T-50T Timing Belt Pulleys Pitch 5.08mm BF-type CNC Drive Pulley Width 11mm

The tooth count determines the pulley's pitch diameter and affects your drive ratio. A smaller tooth count (e.g., XL10T) gives a smaller diameter and is typically used on the motor shaft for speed reduction, while a larger count (e.g., XL50T) on the driven shaft increases torque. Divide the driven pulley tooth count by the drive pulley tooth count to get your reduction ratio. For CNC axes, common ratios range from 1:1 to 1:3 depending on your lead screw or rack pitch.

Measure your motor or drive shaft diameter precisely with calipers. Select the bore option that matches — for example, a NEMA 17 stepper motor typically has a 5mm shaft, while NEMA 23 motors commonly use 6.35mm or 8mm shafts. The BF-type bore includes a set-screw flat, so the shaft must have a corresponding flat ground or filed at the set-screw location for a secure, non-slip connection.

These pulleys have an 11mm body width with integrated flanges. They are designed to work with XL timing belts that are typically 9.5mm (3/8") or 10mm wide, which sit within the flanged groove. Always verify the belt width against the pulley's usable groove width before ordering to ensure the belt tracks correctly without rubbing the flanges.

Aluminum alloy XL pulleys are well-suited for light-to-medium duty CNC routers, laser cutters, and 3D printers operating at typical stepper or servo motor torque levels. For very high-torque or high-speed industrial applications, verify the belt tension limits and pulley tooth shear strength against your system's peak load. The XL profile is rated for lighter loads compared to HTD or GT2 profiles, so confirm your torque requirements match the XL belt system's capacity.

Aluminum alloy naturally forms a thin oxide layer that provides moderate corrosion resistance in typical indoor environments. For humid, wet, or mildly corrosive environments, the pulleys will perform adequately without additional treatment. For harsh outdoor or chemical-exposure environments, consider applying a clear anodize coating or selecting stainless steel alternatives if available. Avoid prolonged contact with strong acids or alkalis.

No. These pulleys are machined specifically for the XL tooth profile (trapezoidal, 5.08mm pitch). GT2 belts use a 2mm pitch curvilinear profile, and HTD belts use a different trapezoidal pitch (typically 3mm, 5mm, or 8mm). Mixing belt profiles and pulleys will result in poor engagement, accelerated wear, and potential belt skipping. Always match the belt profile and pitch to the pulley specification.

BF-type (Bore with Flat) means the pulley has a straight-through bore with a machined flat on the inner surface and a set-screw hole. The set screw presses against the flat on the shaft to prevent rotation. Pilot bore pulleys have a smaller initial bore that you machine to your exact shaft size. Taper lock pulleys use a separate taper bushing for easy installation and removal. BF-type is the simplest and most common choice for fixed-shaft applications where the shaft diameter is already known.