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When a slipping V-belt or misaligned drive component costs you a project deadline, engineers and makers alike know the frustration. This 3M timing pulley is designed for DIYers, robotics builders, CNC hobbyists, and light industrial users who need a reliable, zero-slip synchronous drive solution that installs quickly and holds position under load.
Each 3M timing pulley features an aluminum body with an AF-style fixed flange on one side, machined to the 3M tooth profile (3mm pitch). The tooth width is 7mm, matched to standard 6mm-wide 3M synchronous belts. Available in 15T to 40T tooth counts and bore diameters from 4mm to 25mm (approximately 0.16 in to 0.98 in), with an outer diameter that scales from roughly 14mm (0.55 in) at 15T to approximately 38mm (1.50 in) at 40T.
Typical use cases include 3M belt-driven CNC axis systems requiring repeatable positioning, DIY 3D printer extruder and motion assemblies using 3M synchronous belts, and light-duty conveyor or automation rigs where a compact aluminum timing pulley keeps the drive train tight and backlash-free.
| Belt Pitch | 3M (3mm) |
|---|---|
| Belt Width Compatibility | 6mm |
| Tooth Width | 7mm |
| Tooth Count | 15T – 40T (see variant options) |
| Bore Diameter | 4 – 25mm (see variant options) |
| Flange Type | AF (single-side aluminum flange) |
| Material | Aluminum alloy |
| Outer Diameter (approx.) | See variant options |
| Quantity per Order | 1 piece |
| Weight | See variant options |
The tooth count determines your drive ratio. Divide the driven pulley teeth by the driver pulley teeth to get the ratio — for example, a 15T driver paired with a 30T driven pulley gives a 2:1 reduction (half speed, double torque). For CNC and 3D printer motion axes, 20T is a common starting point. For higher torque at lower speed, choose a larger tooth count on the driver; for higher speed, choose a smaller count.
Match the bore diameter to your shaft diameter. Common stepper motor shafts are 5mm or 6.35mm (¼ in); servo shafts vary from 6mm to 8mm; standard rod stock is often 8mm, 10mm, or 12mm. If your shaft has a keyway, you will need to add a set screw or key after installation — these pulleys use a set-screw style bore. Check your motor or shaft spec sheet before ordering.
No. This pulley is machined to the 3M tooth profile (3mm pitch, trapezoidal). It is not compatible with GT2 (2mm pitch) or HTD 3M (round-tooth) belts. Always pair this pulley with a 3M trapezoidal synchronous belt of 6mm width for correct engagement and zero-slip operation.
Aluminum 3M pulleys are well-suited for light-to-medium duty synchronous drives — typical applications include 3D printers, small CNC routers, pick-and-place machines, and light conveyor systems. For heavy industrial loads, continuous high-torque applications, or environments with aggressive chemicals, consider a steel pulley instead. If in doubt, contact us with your torque and speed requirements.
The AF (aluminum flange) on one side of the pulley acts as a lateral guide to keep the 6mm belt from walking off the pulley face during operation. For most light-duty applications this single flange is sufficient. In high-speed or heavily loaded drives, pairing with a flanged idler on the opposite side of the belt run provides additional security.
No — the bore is machined to a fixed diameter. You cannot enlarge the bore without specialist machining equipment. If your shaft is slightly smaller than the bore, you can use a shaft adapter sleeve or shim. Always select the bore size that matches your shaft diameter exactly from the variant options above.
The outer diameter (OD) of a 3M timing pulley is calculated as: OD = (Teeth × Pitch) ÷ π. For example, a 20T pulley has an OD of approximately 19.1mm (0.75 in), and a 40T pulley has an OD of approximately 38.2mm (1.50 in). Exact OD values for each tooth count are available on request — contact us to confirm before designing your enclosure or frame clearance.
