GT2 Idler Timing Drive Pulleys 14/15/16/18~26 Tooth,For 6mm Belt 3D Printer CNC

Match the tooth count to your existing idler or driven pulley specification. For most Cartesian and CoreXY 3D printers, 20T is the standard drive pulley tooth count, while idler pulleys are often smooth or toothed at 16T–20T. Check your printer's BOM or motion system diagram to confirm. If you're replacing a worn idler, count the teeth on the original part before ordering.

Measure your shaft or idler pin diameter with a caliper before ordering. Common stepper motor shaft diameters are 5mm; common idler pin/bolt diameters are M3 (3mm), M4 (4mm), and M5 (5mm). Choose a bore that matches your shaft with minimal clearance. For keyed shafts, select the corresponding K3 or K4 variant.

Standard bore pulleys rely on a set screw or press fit to secure the pulley to the shaft. K3 and K4 variants have a machined keyway slot (3mm or 4mm wide respectively) that accepts a matching key on the shaft, providing a positive mechanical lock that prevents rotational slip under load. Use keyway variants when the pulley is transmitting torque rather than acting as a free-spinning idler.

Yes. The GT2 2mm-pitch tooth profile is identical for both open-loop (cut-to-length) and closed-loop (loop belt) GT2 belts with 6mm width. These pulleys will mesh correctly with either belt type as long as the belt width is 6mm.

Aluminum alloy pulleys offer significantly higher dimensional stability and load capacity than injection-molded plastic pulleys. They resist deformation under belt tension, maintain tooth geometry over time, and do not creep or warp from heat generated during extended operation — making them a reliable upgrade for machines that run long print or cutting jobs.

Aluminum alloy naturally forms a thin oxide layer that provides moderate corrosion resistance in typical indoor workshop environments. No lubrication is required or recommended on the belt-contact surface, as lubricants can attract debris and degrade belt performance. If operating in a humid or corrosive environment, consider anodized variants or apply a light protective coating to exposed surfaces.

Yes. Toothed variants can function as drive pulleys (when keyed or set-screw secured to a motor shaft) or as toothed idlers (when mounted on a fixed pin with a bearing). For free-spinning idler use, pair the pulley with an appropriately sized bearing inserted into the bore. Smooth-bore variants without keyways are most commonly used as idlers.