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When your motion system demands slip-free synchronization and you can't afford belt skip, the wrong idler pulley becomes the weakest link in your build. Engineers, makers, and machine builders who rely on T5 belt drives need an idler that holds tooth engagement under load — not a smooth flanged wheel that lets the belt wander. These T5 AF-type toothed idler pulleys are designed for exactly that scenario, giving hobbyists and professional integrators a reliable tensioning and routing solution that stays in sync with the rest of the drive train.
Each T5 timing belt pulley in this series features a toothed (AF-type) profile machined to match the T5 belt standard — 5mm pitch, 16mm belt width. The pulley body is typically aluminum alloy, with a bore range of 5mm to 24mm (approximately 0.197" to 0.945") and tooth counts spanning 10 to 60 teeth, giving an effective pitch diameter range of approximately 15.9mm to 95.5mm (0.63" to 3.76"). Flanges are integrated to keep the belt tracking true on the pulley face.
Typical use cases include CNC router X/Y axis belt tensioning, FDM 3D printer CoreXY and Cartesian drive systems requiring toothed idler routing, and industrial conveyor or pick-and-place automation where T5 belt drives need precise tension management without tooth-skip risk. Long-tail applications include RepRap-style printer upgrades, laser cutter gantry systems, and servo-driven linear actuators.
Tooth geometry matches T5 belt pitch (5mm), maintaining positive engagement during tensioning and routing — eliminating the belt slip common with smooth idlers.
Available from 10 to 60 teeth, covering pitch diameters from approximately 15.9mm to 95.5mm (0.63" to 3.76") to suit compact and large-format drive systems alike.
Bore options from 5mm to 24mm accommodate a wide range of shaft diameters, including metric and fractional (6.35mm / 12.7mm) sizes common in mixed-standard builds.
Pulley face width is sized for 16mm T5 belts, with integrated flanges to maintain lateral belt tracking under dynamic load conditions.
Lightweight yet rigid body material keeps rotational inertia low while providing the dimensional stability needed for repeatable positioning in precision motion systems.
Designed for use as a tensioner or belt-path routing pulley — not a drive pulley — allowing flexible belt routing in multi-axis and complex gantry layouts.
| Belt Standard | T5 (5mm pitch) |
|---|---|
| Belt Width | 16mm |
| Pulley Type | AF-Type Toothed Idler |
| Tooth Count Range | 10 – 60 Teeth (see variant options) |
| Bore Diameter Range | 5mm – 24mm (see variant options) |
| Pitch Diameter Range | Approx. 15.9mm – 95.5mm (0.63" – 3.76") |
| Material | Aluminum Alloy (typical) |
| Flange | Integrated, both sides |
| Finish | See variant options |
| Quantity per Order | 1 piece (default); bulk options available |
| Weight | See variant options |
Select the tooth count based on the pitch diameter you need for your belt path geometry. More teeth = larger pulley diameter. For tight-space tensioners, 10–16 teeth are common; for larger routing pulleys or lower belt wrap angles, 20–40 teeth are typical. Match the pitch diameter to your system's center distance and belt length calculations.
Choose the bore that matches your shaft diameter exactly. Available bores include 5, 6, 6.35, 8, 10, 12, 12.7, 14, 15, 16, 17, 18, 19, 20, and 24mm. The 6.35mm and 12.7mm options are fractional inch equivalents (1/4" and 1/2") for mixed-standard builds. If your shaft requires a keyway or set screw, verify the hub wall thickness is sufficient for your bore size.
This is an idler pulley — it is not intended to transmit torque from a motor shaft. It is used to tension the belt or redirect the belt path in your drive system. The AF-type toothed profile ensures the belt teeth engage the pulley, preventing slip during tensioning, which is an advantage over smooth idlers in high-tension or high-speed applications.
This pulley is rated for 16mm wide T5 belts. Using a narrower belt (e.g., 10mm) may work mechanically but the belt will not be fully guided by the flanges. Using a wider belt is not recommended as it will contact the flanges and cause premature wear. For other belt widths, contact us to confirm compatibility.
The pulley body is typically aluminum alloy, which offers a favorable strength-to-weight ratio and natural oxidation resistance suitable for indoor automation, CNC, and 3D printing environments. For high-humidity or wash-down environments, consider applying a light protective coating or contact us to confirm the specific alloy and surface treatment for your application.
Yes — many users mount these pulleys on a bearing pressed onto a fixed shaft or bolt, allowing the pulley to spin freely as a tensioner. The bore diameter you select should match the outer diameter of your bearing's inner race or the shaft you plan to use. Verify the bore and hub dimensions against your bearing selection before ordering.
Use a toothed idler (this product) when the belt wraps around the toothed side of the belt — the teeth must engage the pulley to avoid deformation or skipping. Use a smooth idler only when the belt contacts the flat back side. In most CoreXY 3D printer and CNC gantry designs, toothed idlers are required at the motor-side routing points where the belt's tooth face contacts the idler.
