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When a mismatched or worn pulley causes belt slip, skipped steps, or positioning errors in your motion system, the fix starts with the right synchronous wheel. These 3M timing belt pulleys are engineered for engineers, makers, and machine builders who need reliable, repeatable torque transmission without guesswork. Whether you're replacing a failed component or speccing a new build, this range covers the most common tooth counts and bore sizes in a single listing.
Each pulley is machined from aluminum alloy, featuring a 3mm pitch tooth profile and a 16mm belt-contact width. Tooth counts span 15T to 38T, with through-hole bore diameters ranging from 4mm to 20mm (typically 4–20mm / 0.16–0.79 in). Keyway variants (K 3mm, K 4mm, K 5mm, K 6mm) are available on select bore sizes for positive shaft engagement without set-screw-only retention.
Typical applications include CNC router X/Y axis drives, 3D printer extruder and motion systems, robotic arm joint actuators, conveyor indexing mechanisms, and compact servo-driven automation assemblies where a 3M synchronous belt is already in use.
Available from 15T to 38T, covering a broad gear ratio spectrum for speed reduction or torque multiplication in compact drive trains.
3mm pitch tooth geometry ensures accurate meshing with standard 3M synchronous belts, minimizing backlash and maintaining positional accuracy over time.
Through-hole bores from 4mm to 20mm accommodate a wide range of motor and shaft diameters. Keyway variants available for positive shaft locking.
Lightweight yet rigid aluminum body keeps rotational inertia low — ideal for high-cycle, high-acceleration motion profiles in CNC and robotics.
Designed for 16mm wide 3M timing belts, providing sufficient load capacity for most light-to-medium duty synchronous drive applications.
Select bore sizes include machined keyways (K 3mm, K 4mm, K 5mm, K 6mm) for torque-positive shaft connections that resist rotational slip under load.
| Belt Pitch | 3M (3mm) |
|---|---|
| Belt Width | 16mm (0.63 in) |
| Tooth Count Range | 15T – 38T |
| Through-Hole Bore Range | 4mm – 20mm (0.16 – 0.79 in) |
| Keyway Options | K 3mm, K 4mm, K 5mm, K 6mm (select variants) |
| Material | Aluminum alloy |
| Tooth Profile | 3M synchronous (trapezoidal) |
| Hub Width | 16mm |
| Weight | See variant options |
| Surface Finish | See variant options |
| Quantity per Order | 1 piece |
The tooth count determines your drive ratio. Divide the driven pulley teeth by the driving pulley teeth to get the reduction ratio. For example, a 15T driver paired with a 30T driven pulley gives a 2:1 reduction (half speed, double torque). Match your required RPM and torque output to select the appropriate pairing. For CNC and 3D printers, common driver tooth counts are 15T–20T on the motor side.
Measure your motor or drive shaft diameter precisely with calipers. Select the bore that matches your shaft exactly — common NEMA 17 stepper motor shafts are 5mm, NEMA 23 are typically 6.35mm or 8mm, and servo motors vary widely. If your shaft has a flat (D-cut) or keyway, choose a keyway variant (e.g., 8mm - K 3mm) for a positive, slip-resistant connection.
Yes — these pulleys are designed for standard 3M pitch (3mm tooth spacing) timing belts with 16mm width. Verify that your belt is labeled "3M" and is 16mm wide. If your belt is a different pitch (e.g., 2M, 5M, GT2, HTD) or a different width, this pulley will not mesh correctly.
For light-duty or low-torque applications (e.g., 3D printer extruders), a plain through-hole bore secured with a set screw is typically sufficient. For higher torque, high-cycle, or precision positioning applications (e.g., CNC axes, servo drives), a keyway variant provides a mechanically positive connection that prevents rotational slip even if the set screw loosens over time.
Aluminum alloy pulleys are well-suited for light-to-medium duty synchronous drives, including CNC routers, 3D printers, robotic arms, and small conveyor systems. They offer a good balance of strength, low rotational inertia, and corrosion resistance. For very high torque or heavy industrial loads, consider whether a steel pulley would be more appropriate for your specific load case.
Use the two variant selectors: first choose your tooth count and belt width (e.g., "3M - 20 Teeth - 16mm"), then select your bore size (e.g., "8mm" for plain bore, or "8mm - K 3mm" for a keyway bore). Cross-reference your motor shaft diameter and keyway dimensions before adding to cart. If you are unsure, contact us with your motor model number and we can confirm compatibility.
Aluminum alloy has inherent oxidation resistance and performs well in typical indoor workshop and light industrial environments. For prolonged exposure to moisture, salt spray, or aggressive chemicals, consider applying a protective coating or anodizing treatment. These pulleys are not rated for submersion or harsh outdoor weathering without additional protection.
