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When a slipping or mismatched pulley costs you a failed print or a mis-cut workpiece, the fix starts with the right HTD 8M timing belt pulley. Designed for engineers, makers, and machine builders who need repeatable, backlash-free power transmission, these pulleys are a direct-fit solution for any 8M pitch synchronous belt drive system.
Each pulley is machined from aluminum alloy with an anodized finish, available in tooth counts from 10T to 25T and bore diameters from 6 mm (0.24 in) to 28 mm (1.10 in). Plain bore and keyed bore variants (K3, K4, K5, K6, K8 keyway options) are offered. All variants accept a 30 mm (1.18 in) wide HTD 8M belt.
Typical use cases include CNC router X/Y axis drives, FDM 3D printer extruder and motion systems, conveyor and indexing table drives, and general industrial automation where an HTD 8M synchronous belt pulley replacement or upgrade is required.
| Belt Pitch | 8M (8 mm pitch, HTD profile) |
|---|---|
| Tooth Count (T) | 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 25 |
| Bore Diameter | 6–28 mm (plain); keyed options: K3, K4, K5, K6, K8 |
| Applicable Belt Width | 30 mm |
| Material | Aluminum alloy |
| Surface Treatment | Anodized |
| Bore Type | Plain bore or keyed bore (see variant options) |
| Keyway Size | See variant options |
| Flange | Double flange (standard) |
| Weight | See variant options |
The tooth count determines your drive ratio and belt speed. Divide the driven pulley teeth by the driver pulley teeth to get the reduction ratio. For CNC routers and 3D printers, 16T–20T on the motor shaft paired with a larger driven pulley is common. If you are replacing an existing pulley, match the tooth count exactly to maintain your steps-per-mm calibration.
Measure your motor or shaft diameter with a caliper. Select the plain bore size that matches your shaft (e.g., 8 mm shaft → 8 mm bore). If your shaft has a keyway, choose the corresponding keyed bore variant (e.g., 10K3 = 10 mm bore with a 3 mm keyway). Bore sizes range from 6 mm to 28 mm across the range.
A plain bore pulley is secured to the shaft using a set screw only — suitable for lighter loads and applications where the shaft has no keyway. A keyed bore pulley has a machined slot (keyway) that accepts a key, providing a positive mechanical connection that prevents rotation under high torque. The number after K indicates the keyway width in millimetres (e.g., K4 = 4 mm keyway).
Yes — all variants in this listing are designed for standard HTD 8M pitch synchronous belts with a 30 mm belt width. Confirm your belt is 8M pitch (8 mm tooth-to-tooth spacing) and 30 mm wide before ordering. These pulleys are not compatible with T8, GT2, or other pitch profiles.
Aluminum alloy pulleys are well-suited for CNC, 3D printing, and light-to-medium industrial automation loads. The HTD curved tooth profile distributes belt tension across multiple teeth simultaneously, reducing peak stress. For very high-torque or heavy-duty industrial applications requiring steel pulleys, please contact us to confirm suitability before ordering.
Yes. The anodized coating provides a hard, oxide layer that resists oxidation and mild chemical exposure typical of workshop environments. It is not rated for immersion in harsh acids or salt-spray environments. For outdoor or wet-environment use, consider applying a light machine oil to the bore and shaft interface.
NEMA 17 motors typically have a 5 mm shaft — select the 6 mm plain bore (smallest available) and use a shaft adapter, or confirm your motor has a larger shaft. NEMA 23 motors commonly use 6.35 mm (1/4 in) or 8 mm shafts — select the 8 mm plain bore or 8K3 keyed bore accordingly. Always verify your motor's shaft diameter in its datasheet.
