2GT 20-80T Timing Pulley Pitch 2mm Without Step AF-type Width 10mm For 3D Printe

The tooth count determines your drive ratio. For a 1:1 ratio (same speed on both shafts), use identical tooth counts on driver and driven pulleys. To reduce speed and increase torque, use a smaller driver pulley (e.g., 20 T) paired with a larger driven pulley (e.g., 40 T), giving a 2:1 reduction. Most 3D printer X/Y axes use a single 20 T driver pulley with the belt running directly to the carriage, so a 20 T is the most common choice for that use case.

Standard NEMA 17 stepper motors have a 5 mm output shaft. Select the 5 mm bore variant. If your motor has a D-cut (flat) shaft, the set screw in the pulley hub will lock onto the flat for a secure, slip-free connection. For NEMA 23 motors, the standard shaft is 6.35 mm (1/4 inch) — choose the 6.35 mm bore variant.

Yes. The 2GT tooth profile is dimensionally identical to the GT2 profile — both use a 2 mm pitch and the same tooth geometry. These pulleys are compatible with any GT2 or 2GT open-loop or closed-loop timing belt with an 11 mm width. Belts wider or narrower than 11 mm are not recommended as they may not seat correctly in the pulley groove.

AF-type (also called "no-step, no-flange") means the pulley hub is a plain cylinder without raised flanges on the sides of the belt groove. Flanged pulleys have raised edges that help keep the belt centered on the pulley. AF-type pulleys rely on belt tension and system alignment to keep the belt tracking. They are lighter and easier to install in tight spaces, and are the standard choice for most 3D printer and laser cutter builds where the belt path is well-constrained by the frame geometry.

The aluminum alloy hub is adequate for the torque loads typical of desktop 3D printers, laser engravers, and small CNC routers. The set screw provides the primary locking force; ensure it is tightened against the flat of a D-cut shaft or directly onto a round shaft with thread-locking compound for best results. For high-torque industrial applications exceeding the rated capacity of desktop stepper motors, a steel pulley may be more appropriate.

Yes, each pulley includes a set screw pre-installed in the hub. The set screw typically requires a 1.5 mm or 2 mm hex (Allen) key depending on the bore size variant. Tighten the set screw firmly against the motor shaft flat after aligning the pulley at the correct axial position. If your shaft is round (no flat), apply a small amount of thread-locking compound to prevent loosening under vibration.

Yes. Larger tooth-count variants (e.g., 40 T, 60 T, 80 T) are commonly used as driven pulleys in belt-reduction stages for Z-axis lead screws, providing a mechanical advantage that improves micro-stepping resolution and reduces motor holding torque requirements. Pair with a smaller driver pulley (e.g., 20 T) for a 2:1 or higher reduction ratio.