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When a slipping or mismatched pulley causes positioning errors in your CNC router, 3D printer, or linear actuator, the entire project stalls. Engineers and makers who need repeatable, backlash-free motion rely on a pulley that holds its tooth profile under load — and that is exactly what these 3M timing belt pulleys are designed to deliver.
Each pulley is machined from aluminum alloy with a hard-anodized finish, featuring a 3M tooth pitch (3mm center-to-center). Tooth counts range from 20T to 100T, bore diameters from 8mm (0.31 in) to 25mm (0.98 in), and keyway widths from 3mm to 8mm depending on the variant. A machined step and keyway slot ensure positive shaft locking when used with a set screw or key.
Typical use cases include open-loop stepper-driven CNC gantries requiring consistent belt tension, desktop 3D printer X/Y axis drives where tooth skip causes layer shifts, and compact conveyor or pick-and-place automation where a low-profile 10mm-wide belt drive saves space compared to chain or gear systems.
| Belt Pitch | 3M (3mm) |
|---|---|
| Compatible Belt Width | 10mm |
| Tooth Count (Types) | 20T, 24T, 25T, 30T, 32T, 35T, 36T, 38T, 40T, 50T, 60T, 65T, 70T, 72T, 75T, 80T, 90T, 100T |
| Bore Diameter Range | 8mm – 25mm (0.31 in – 0.98 in) |
| Keyway Width × Height | 3×1.4mm / 4×1.8mm / 5×2.3mm / 6×2.8mm / 8×3.3mm (see variant options) |
| Material | Aluminum alloy |
| Finish | Hard anodized |
| Shaft Locking | Step shoulder + keyway slot (set screw not included) |
| Quantity per Order | 1 pc |
| Weight | See variant options |
The tooth count determines the pulley's pitch diameter and, combined with your motor pulley, sets the drive ratio. For a 1:1 drive use matching tooth counts on both ends. For speed reduction, use a larger tooth count on the driven side. A 20T pulley at 3M pitch has a pitch diameter of approximately 19.1mm (0.75 in), while a 100T pulley reaches about 95.5mm (3.76 in).
Match the keyway to the standard key size for your shaft diameter. Common pairings: 8–10mm bore → 3×1.4mm key; 10–12mm bore → 4×1.8mm key; 12–17mm bore → 5×2.3mm key; 17–22mm bore → 6×2.8mm key; 22–25mm bore → 8×3.3mm key. Always verify against your shaft's actual keyway specification before ordering.
No. These pulleys use the 3M trapezoidal tooth profile, which is not interchangeable with GT2 (2mm pitch) or HTD 3M (rounded tooth) profiles. Always pair with a 3M trapezoidal timing belt of 10mm width for correct tooth engagement and load capacity.
Aluminum alloy pulleys are well-suited for light-to-medium duty CNC, 3D printing, and automation drives. For continuous high-torque industrial applications exceeding the belt's rated tension, consider whether a steel pulley is more appropriate. In typical desktop CNC and 3D printer use, aluminum pulleys handle the load without deformation.
The hard-anodized finish provides good oxidation resistance for indoor workshop conditions. Anodizing creates a hard aluminum oxide layer that resists moisture and minor chemical exposure. Avoid prolonged exposure to salt spray or strong acids, which can degrade the anodized layer over time.
No fasteners or keys are included. The pulley ships as a single machined component. You will need to source a matching key (Woodruff or parallel) for the keyway slot and a set screw if your shaft requires one. Standard metric keys are widely available at hardware and engineering suppliers.
Yes. Select the variant with a 12.7mm bore. This bore size is available on several tooth count options including 3M-25T(K-Type), 3M-32T, 3M-36T, 3M-38T, and 3M-40T. Check the variant table to confirm availability for your specific tooth count before ordering.
