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When your CNC router skips steps or your 3D printer loses positional accuracy, the culprit is often a poorly fitted pulley. Engineers, makers, and machine builders who demand repeatable motion need a timing belt pulley that locks firmly onto the shaft and transfers torque without slip. These HTD5M pulleys are designed for exactly that — precision synchronous drive in demanding motion-control applications.
Each pulley is machined from aluminum alloy and features an HTD5M tooth profile (5 mm pitch) with a keyed bore for positive shaft engagement. Belt width options are 15 mm (~0.59 in) and 20 mm (~0.79 in). Tooth counts span 15 to 100, giving pitch diameters from approximately 23.9 mm (0.94 in) for a 15-tooth pulley up to approximately 159.2 mm (6.27 in) for a 100-tooth pulley. Bore diameters range from 8 mm to 40 mm depending on the variant selected.
Typical use cases include CNC router X/Y axis drives requiring low backlash synchronous motion, 3D printer extruder and gantry belt drive systems, and stepper-motor-driven automation stages where consistent step-to-distance ratio is critical.
Each pulley ships with a machined keyway slot, eliminating shaft slip under load and maintaining accurate step-to-distance ratios in CNC and stepper motor applications.
The 5 mm pitch HTD (High Torque Drive) curvilinear tooth form distributes belt load across a larger contact area than trapezoidal profiles, reducing tooth stress and extending belt life.
Fourteen tooth-count options let you dial in the exact gear ratio your drive system needs — from compact 15-tooth driver pulleys to large 100-tooth driven pulleys for high-reduction stages.
Available in 15 mm and 20 mm belt widths to match your existing HTD5M belt stock. The 20 mm width handles higher torque loads for heavier gantry or spindle drive applications.
Lightweight aluminum keeps rotational inertia low — important for stepper motors that must accelerate and decelerate rapidly — while providing adequate strength for typical CNC and automation loads.
Bore diameters from 8 mm to 40 mm (depending on tooth count) with matching keyway dimensions, so you can match the pulley directly to your motor shaft or lead screw without custom machining.
| Belt Profile | HTD5M (5 mm pitch, curvilinear tooth) |
|---|---|
| Tooth Count Options | 15, 16, 18, 20, 22, 24, 25, 30, 35, 40, 45, 50, 60, 100 |
| Belt Width Compatibility | 15 mm / 20 mm |
| Bore Diameter | See variant options (8 mm – 40 mm) |
| Keyway Dimensions | See variant options (e.g. 3×1.4 mm, 4×1.8 mm, 5×2.3 mm, 6×2.8 mm, 8×3.3 mm) |
| Material | Aluminum alloy |
| Pitch Diameter (15T) | Approx. 23.9 mm (0.94 in) |
| Pitch Diameter (20T) | Approx. 31.8 mm (1.25 in) |
| Pitch Diameter (40T) | Approx. 63.7 mm (2.51 in) |
| Pitch Diameter (100T) | Approx. 159.2 mm (6.27 in) |
| Quantity per Order | 1 piece |
| Finish | Natural aluminum (uncoated) |
The tooth count determines the pitch diameter and, combined with your driven pulley's tooth count, sets the drive ratio. For a 1:1 ratio use matching tooth counts on both pulleys. For speed reduction (more torque), use a smaller driver pulley and a larger driven pulley — for example, a 20-tooth driver with a 40-tooth driven pulley gives a 2:1 reduction. Calculate the required center distance and belt length using the pitch diameters before ordering.
Match the bore diameter to your motor shaft diameter. Common NEMA 17 stepper motors use a 5 mm shaft, but these pulleys start at 8 mm bore — suitable for NEMA 23 (6.35 mm or 8 mm shaft) and larger motors. Check your motor's datasheet for the shaft diameter and keyway dimensions before selecting a variant. The keyway dimensions are listed in the variant name (e.g., "8mm(3×1.4mm)" means 8 mm bore with a 3×1.4 mm keyway).
Yes. These pulleys are machined to the HTD5M standard (5 mm pitch, curvilinear tooth profile) and are compatible with any HTD5M timing belt of the matching width (15 mm or 20 mm). They are not compatible with GT2, T5, or other belt profiles — the tooth geometry is specific to HTD5M.
Belt width affects the torque capacity of the drive. A 20 mm wide belt and matching pulley can transmit more torque than a 15 mm combination because the belt contact area is larger. For light-duty CNC axes and 3D printer gantries, 15 mm is typically sufficient. For heavier spindle drives or high-force linear stages, the 20 mm option provides a greater safety margin.
The pulleys are machined from aluminum alloy, which offers a good strength-to-weight ratio for typical CNC and automation loads. Aluminum pulleys are well-suited for stepper and servo motor drives where keeping rotational inertia low is important. For very high-torque industrial applications, consider whether a steel pulley would be more appropriate for your load requirements.
The pulleys include a machined keyway slot but do not include the key itself. You will need to source a parallel key that matches the keyway dimensions listed in your chosen variant (e.g., a 3×1.4 mm or 5×2.3 mm key). Standard parallel keys are widely available from hardware and engineering suppliers.
Yes. The keyed bore design provides the positive shaft engagement needed for closed-loop servo systems where any slip between the pulley and shaft would cause encoder feedback errors. Ensure the bore and keyway dimensions match your servo motor shaft specifications before ordering.
