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When your CNC router skips steps, your 3D printer loses position, or your conveyor drifts out of sync, the culprit is often a worn or mismatched pulley. This 3M timing belt pulley is engineered for makers, engineers, and automation builders who need reliable, slip-free power transmission without the guesswork. Available in 38 to 65 teeth configurations with a 16mm belt tooth width, it pairs directly with standard 3M pitch synchronous belts.
Each pulley is machined from aluminum alloy with a natural or anodized finish. The bore diameter ranges from 5mm to 25mm (0.20" to 0.98"), and keyway variants are available for positive shaft engagement. Tooth count options span 38T, 40T, 42T, 44T, 45T, 46T, 48T, 50T, 52T, 54T, 56T, 58T, 60T, and 65T — all with a 3mm pitch and 16mm tooth width (approximately 0.63").
Typical use cases include DIY CNC machine X/Y axis drives, desktop 3D printer extruder and motion systems, small conveyor belt assemblies, and robotics joint actuators requiring precise angular positioning. Long-tail search terms like "3M 16mm timing pulley with keyway" and "3M synchronous wheel 50 teeth aluminum" describe exactly what this product delivers.
Available from 38T to 65T, letting you dial in the exact gear ratio for your drive system without custom machining.
Matches standard 3M synchronous belts. The 16mm (0.63") tooth width provides solid belt engagement and lateral stability.
Choose a plain through-hole (5–25mm) or a keyway bore (e.g., 10mm + K3mm) for positive, non-slip shaft coupling in high-torque applications.
Lightweight yet rigid aluminum body keeps rotational inertia low — ideal for high-speed CNC and robotics applications where acceleration matters.
Bores are machined to close tolerances for minimal runout, ensuring smooth, vibration-free operation across the full RPM range of your drive.
Over 200 SKU combinations of tooth count × bore size available in one listing — find your exact spec without ordering from multiple suppliers.
| Belt Pitch | 3mm (3M) |
|---|---|
| Tooth Width | 16mm (approx. 0.63") |
| Tooth Count Options | 38T, 40T, 42T, 44T, 45T, 46T, 48T, 50T, 52T, 54T, 56T, 58T, 60T, 65T |
| Bore Diameter Range | 5mm – 25mm (0.20" – 0.98") |
| Keyway Options | K3mm, K4mm, K5mm, K6mm, K8mm (see variant options) |
| Material | Aluminum alloy |
| Finish | See variant options |
| Compatible Belt Width | 15mm – 16mm |
| Outer Diameter | See variant options |
| Hub Style | Single flange with set-screw boss (through-hole) or keyway bore |
| Quantity per Order | 1 piece |
The tooth count determines the pulley's pitch diameter and, combined with your driven pulley's tooth count, sets the drive ratio. For a 1:1 ratio use identical tooth counts on both pulleys. For speed reduction, use a larger tooth count on the driven side. Common CNC and 3D printer setups use 20T–40T on the motor and a matching or larger pulley on the driven axis. This listing covers 38T to 65T, suitable for driven-side or large-motor-side applications.
A through-hole (plain bore) pulley relies on a set screw to grip the shaft. This is sufficient for light-to-medium torque applications. A keyway bore adds a rectangular slot that mates with a key on the shaft, providing a positive mechanical lock that prevents rotational slippage under high torque or shock loads — recommended for conveyor drives, servo motors, and any application where precise positioning is critical.
Yes, provided your belt has a 3mm pitch (tooth-to-tooth spacing of 3mm) and a width of 15mm or 16mm. Verify both the pitch and width of your belt before ordering. A 3M belt is not compatible with GT2, HTD, or other pitch standards even if the tooth count matches.
Aluminum alloy offers good natural corrosion resistance for indoor and light-industrial environments. For humid or outdoor applications, an anodized finish provides additional protection. If your application involves exposure to cutting fluids, saltwater, or harsh chemicals, consider adding a protective coating or selecting a stainless steel alternative for critical components.
Yes. Select the bore diameter that matches your stepper motor shaft — common sizes are 5mm, 6mm, 6.35mm (1/4"), 8mm, and 10mm. For NEMA 17 motors the shaft is typically 5mm; for NEMA 23 it is typically 6.35mm or 8mm. If your motor shaft has a flat (D-cut), a set screw through-hole bore will grip it securely. For a round shaft under high torque, choose a keyway variant.
The pitch diameter (PD) of a 3M pulley is calculated as: PD = (Teeth × Pitch) ÷ π. For example, a 40T pulley has PD = (40 × 3) ÷ 3.1416 ≈ 38.2mm. The outer diameter is slightly larger than the pitch diameter. Exact outer diameter values vary by tooth count — please refer to the variant options or contact us to confirm the OD for your specific selection.
The keyway dimensions follow standard metric key sizing conventions. For example, a 10mm bore with K3mm keyway uses a 3×3mm key; a 15mm bore with K5mm uses a 5×5mm key. Match the keyway width to the key already cut on your shaft, or have a machinist cut a matching keyway on a new shaft. The key itself is not included and must be sourced separately.
