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When your CNC router skips steps or your 3D printer loses position mid-print, the culprit is often a loose or mismatched pulley bore. Engineers, makers, and automation builders who demand repeatable motion need a pulley that locks firmly onto the shaft and stays there. This HTD5M timing belt pulley is designed for exactly that — a clamping-style bore that grips the shaft mechanically, eliminating set-screw slippage under load.
Each pulley is machined from aluminum alloy and features the HTD5M tooth profile (5 mm pitch, rounded tooth form) compatible with standard HTD5M synchronous belts. Available in 15, 16, 18, 20, and 25 tooth counts, belt widths of 15 mm (~0.59 in) and 20 mm (~0.79 in), and bore diameters ranging from 5 mm to 20 mm (~0.20–0.79 in). Two flange shapes are offered: BF (with flanges) and K (keyway-style clamping hub).
Typical applications include DIY CNC milling machines requiring precise X/Y axis synchronization, FDM 3D printer extruder and motion systems, laser engraver gantry drives, and light-duty conveyor or indexing table builds where a 5 mm pitch HTD belt drive is specified.
| Belt Profile | HTD5M (5 mm pitch, rounded tooth) |
|---|---|
| Tooth Count Options | 15 / 16 / 18 / 20 / 25 teeth |
| Belt Width Compatibility | 15 mm (~0.59 in) / 20 mm (~0.79 in) |
| Bore Diameter Range | 5 mm – 20 mm (see variant options) |
| Flange / Hub Style | BF (flanged) or K (keyway clamping hub) |
| Material | Aluminum alloy |
| Finish | Natural anodized / machined surface |
| Outer Diameter | See variant options |
| Hub Clamping Method | Mechanical clamping bore (split-hub or keyway) |
| Quantity per Order | 1 piece |
The tooth count determines the pulley's pitch diameter and, combined with your motor shaft speed, sets the linear belt speed. For CNC and 3D printer motion systems, 20-tooth pulleys are a common starting point as they balance speed and torque. Fewer teeth (15–16) give more torque at lower speed; more teeth (25) increase speed at a given RPM. Match the tooth count on both the drive and driven pulleys to achieve your desired gear ratio.
BF (flanged) pulleys have raised flanges on both sides of the tooth face that keep the belt from walking off laterally — useful when belt alignment cannot be guaranteed mechanically. K-style pulleys feature a keyway clamping hub designed for keyed shafts, providing a more positive torque connection suitable for higher-load applications. Choose BF for most open-loop 3D printer and light CNC builds; choose K when your motor shaft has a keyway and you need maximum torque transfer.
Measure your motor or drive shaft diameter with a caliper. Common stepper motor shaft sizes are 5 mm, 6 mm, 6.35 mm (1/4 in), and 8 mm. Select the bore that matches your shaft exactly — the clamping bore design allows a secure fit without requiring a perfectly tight interference fit, but the bore must not be larger than the shaft. If your shaft is between listed sizes, contact us to confirm availability.
No. This pulley uses the HTD5M tooth profile (5 mm pitch, rounded/curvilinear tooth form), which is not interchangeable with GT2 (2 mm pitch) or MXL (0.08 in pitch) belts. Always pair HTD5M pulleys with HTD5M belts of the matching width (15 mm or 20 mm). Using a mismatched belt profile will cause skipping and accelerated wear.
The clamping bore (split-hub or keyway style) provides a mechanical grip on the shaft that is significantly more secure than a single set screw alone. For typical CNC router and 3D printer stepper motor torques (generally under 1 Nm for NEMA 17, up to ~3 Nm for NEMA 23), the clamping hub holds reliably when the clamping bolt is tightened to the recommended torque. For very high-torque or shock-load applications, the K-style keyway variant is recommended.
Aluminum alloy has natural corrosion resistance suitable for indoor workshop and machine environments. The anodized or machined surface finish provides additional protection against oxidation. For outdoor or high-humidity environments, periodic inspection is recommended. The tooth surface hardness is adequate for use with rubber or polyurethane HTD5M belts under normal operating loads; abrasive environments may accelerate tooth wear over time.
Yes. NEMA 17 stepper motors typically have a 5 mm shaft — select the 5 mm bore variant. NEMA 23 motors commonly use 6.35 mm (1/4 in) or 8 mm shafts — select the matching bore. Always verify your specific motor's shaft diameter in its datasheet before ordering, as shaft sizes can vary between manufacturers even within the same NEMA frame size.
