GT2 2GT 60T-78T Timing Belt Pulleys 5mm-20mm Bore with Steps for CNC 3D Printer

The tooth count determines your drive ratio. Pair this pulley with a smaller driver pulley (e.g., 20T) to achieve the reduction ratio you need. For example, a 60T driven pulley with a 20T driver gives a 3:1 reduction. Higher tooth counts increase the belt contact arc and reduce tooth load, which is useful for high-torque or high-speed applications.

Measure your motor shaft diameter precisely before ordering. Common NEMA 17 stepper shafts are 5mm; NEMA 23 shafts are typically 6.35mm (1/4") or 8mm. If your shaft is keyed, select the matching keyway variant (e.g., 8mm bore with K 3mm keyway). Contact us to confirm if you are unsure.

A through-hole (plain bore) pulley relies on set screws to grip the shaft. A keyway variant has a machined slot that accepts a key inserted between the shaft and pulley, providing a positive torque connection that prevents rotational slipping under load. Keyway variants are recommended for high-torque or reversing-load applications.

Yes. These pulleys are machined to the GT2 / 2GT 2mm-pitch profile and are compatible with standard GT2 timing belts in 6mm or 7mm widths. The groove is sized for 7mm belt width. Using a 6mm belt is generally acceptable but may result in slightly reduced belt contact. Always verify belt width compatibility with your specific belt supplier's specifications.

These aluminum alloy pulleys are suitable for typical desktop CNC router and 3D printer loads. For very high-speed or heavy-duty industrial applications, verify that the pulley's rated torque capacity matches your system's peak load. The step flange design helps maintain belt tracking under dynamic loads.

Aluminum alloy naturally forms a thin oxide layer that provides moderate corrosion resistance in typical indoor workshop environments. For humid or chemically aggressive environments, consider applying a light coating of machine oil to exposed surfaces. These pulleys are not rated for outdoor or marine use.

Yes, using identical tooth counts on both sides gives a 1:1 drive ratio, which is common in CoreXY 3D printer gantry systems where both pulleys are the same size. Ensure your belt length is calculated correctly for the center-to-center distance of your specific machine layout.