HTD-8M 18T-60T Timing Belt Pulley With Expansion/Tension Sleeve Teeth Width 27mm

The tooth count determines the pitch diameter of the pulley (PD = Teeth × Pitch / π). For a given belt speed, a higher tooth count gives a larger pulley diameter and lower shaft RPM. To calculate your speed ratio, divide the driven pulley tooth count by the driving pulley tooth count. For example, an 18T driver paired with a 36T driven pulley gives a 2:1 reduction. Select tooth counts that achieve your target ratio while keeping the center distance within your belt's available lengths.

The sleeve bore range varies by variant — options span from 8mm up to 50mm. Each variant listing specifies the exact sleeve bore size. The expansion sleeve clamps concentrically onto the shaft when the fastening bolts are tightened, so the bore must match your shaft diameter. If your shaft is between standard sizes, select the next size up and verify the sleeve's minimum bore specification before ordering.

Yes. This pulley is designed for the HTD-8M profile — 8mm pitch with a curvilinear (rounded) tooth form. It is not compatible with trapezoidal MXL, XL, L, or T-profile belts of the same pitch. Ensure your belt is specifically rated for HTD-8M. The teeth width of 27mm is compatible with 25mm and 30mm wide HTD-8M belts; confirm belt width compatibility with your specific belt supplier.

When properly torqued to the manufacturer's specification, the expansion sleeve creates a friction-fit clamp that distributes clamping force evenly around the shaft circumference. This provides significantly higher torque transmission than a single set screw. For high-shock or reversing-load applications, ensure the sleeve bolts are tightened to the correct torque and consider using thread-locking compound on the fasteners. The aluminum pulley body is suitable for moderate-to-high torque drives typical of CNC and robotics applications.

The pulley body is machined from aluminum alloy with an anodized surface treatment, which provides good resistance to oxidation and mild corrosion in typical indoor industrial and workshop environments. It is not rated for immersion or exposure to strong acids, alkalis, or salt spray. For outdoor or wash-down environments, consider additional protective coatings or stainless steel alternatives.

Yes. The expansion sleeve design is well-suited for stepper and servo motor shafts because it does not require a keyway and does not create stress concentrations from set screws. Select the bore size that matches your motor shaft diameter. For NEMA 17 motors (5mm shaft), NEMA 23 (6.35mm or 8mm shaft), and larger servo motors, choose the corresponding sleeve bore variant. Verify the pulley's pitch diameter fits within your motor's rated radial load specification.

A standard bored pulley has a fixed bore machined to a specific diameter, often requiring a keyway and set screw for shaft retention. An expansion sleeve pulley uses a split tapered sleeve that clamps onto the shaft when tightened, allowing it to fit a range of shaft diameters and be repositioned or removed without damaging the shaft. This makes expansion sleeve pulleys more versatile for prototyping, easier to align, and gentler on precision shafts — at the cost of slightly higher initial price compared to plain-bore versions.