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When a slipping or mismatched pulley is costing you accuracy on your CNC router, 3D printer, or automation rig, you need a drop-in HTD-3M timing belt pulley that fits right the first time. These HTD-3M timing belt pulleys are engineered for makers, engineers, and machine builders who demand repeatable, zero-slip power transmission in compact drive systems.
Each pulley is machined from aluminum alloy with an anodized finish, featuring a 3mm HTD tooth pitch and a 16mm belt-contact width. Bore sizes range from 8mm to 25mm (approximately 0.31" to 0.98"), with tooth counts spanning 14T to 65T to suit a wide range of gear ratios. Two hub styles are available: K-type (standard cylindrical hub) and BF-type (flanged hub for improved belt retention). All variants include a precision-cut keyway for positive shaft engagement.
Typical use cases include CNC axis drives requiring HTD-3M belt pulley replacement, 3D printer X/Y motion systems using 3mm pitch timing pulleys, and light industrial conveyor or indexing systems needing a keyed timing pulley with 16mm belt width.
| Tooth Profile | HTD (High Torque Drive), 3mm pitch |
|---|---|
| Number of Teeth | 14T – 65T (see variant options) |
| Belt Width Compatibility | 16mm |
| Hub Style | K-type (cylindrical) / BF-type (flanged) |
| Bore Diameter | 8mm – 25mm (see variant options) |
| Keyway Dimensions | 3×1.4mm / 4×1.8mm / 5×2.3mm / 6×2.8mm / 8×3.3mm (matched to bore) |
| Material | Aluminum alloy |
| Surface Finish | Anodized |
| Pitch Diameter Range | Approx. 13.4mm – 62.1mm (varies by tooth count) |
| Quantity per Order | 1 piece |
| Weight | See variant options |
Your drive ratio is determined by the tooth count ratio between the driving and driven pulleys. For example, a 20T motor pulley paired with a 40T axis pulley gives a 2:1 reduction. Calculate your required ratio first, then select tooth counts that fit within your available center distance. Use the pitch diameter formula: PD = (Teeth × Pitch) ÷ π to verify physical clearance.
K-type pulleys have a plain cylindrical hub on both sides — compact and suitable when your belt is constrained by side guides or the machine frame. BF-type pulleys have a flange on one side that acts as a belt retainer, preventing the belt from walking off the pulley laterally. BF-type is recommended for open-frame CNC machines and 3D printers where lateral belt drift is a concern.
Keyway dimensions are matched to bore size: 8mm bore → 3×1.4mm keyway; 10–12mm bore → 3×1.4mm or 4×1.8mm; 12.7–15mm bore → 5×2.3mm; 16–20mm bore → 5×2.3mm or 6×2.8mm; 22–25mm bore → 8×3.3mm. The exact keyway for each variant is listed in the variant name under "Keyway & Amount".
Yes — all pulleys in this listing use the standard HTD 3mm tooth profile and are designed to mesh with any HTD-3M timing belt of 16mm width. Confirm your belt's pitch (3mm) and width (16mm) before ordering. These pulleys are not compatible with GT2, MXL, or T5 belts.
Use a digital caliper to measure the outer diameter of your motor or lead-screw shaft at the point where the pulley will sit. Select the bore size that matches your shaft diameter exactly. Common motor shaft sizes: NEMA 23 stepper → 6.35mm (listed as 12.7mm = 1/2"), servo motors → 8–20mm range.
These aluminum HTD-3M pulleys are well-suited for light-to-medium duty CNC, 3D printing, and automation applications running at typical stepper or servo motor speeds (up to approximately 3,000–5,000 RPM depending on tooth count and belt tension). The HTD tooth profile handles higher torque than trapezoidal profiles of the same pitch.
The keyway provides positive rotational locking between the shaft and pulley. For most CNC and 3D printer applications, a keyway alone is sufficient when the shaft and pulley bore are properly matched. If your application involves frequent direction reversals or shock loads, adding a set screw over the keyway slot provides additional axial retention.
