HTD-5M 15T-72T Timing Belt Pulleys CNC Drive With Keyway Width 11mm BF 45# Steel

The tooth count determines the pitch diameter and, combined with the tooth count of the mating pulley, sets your drive ratio. Divide the driven pulley tooth count by the driving pulley tooth count to get the speed-reduction ratio. For CNC and 3D-printer applications, common pairings are 20T/40T (2:1) or 16T/32T (2:1). If you are replacing an existing pulley, match the tooth count exactly.

Measure your shaft diameter with a caliper. Select the bore that matches your shaft — the keyway provides the positive drive connection, so a slip fit (H7 tolerance) is normal. Available bores are 8, 10, 12, 12.7, 14, 15, 16, 17, 18, 19, 20, 22, 24, 25, 28, and 30 mm. If your shaft is imperial (e.g., 1/2 in = 12.7 mm), select the 12.7 mm bore option where available.

Keyway dimensions follow DIN 6885 standards and are listed in the "Keyway & Amount" variant option. Smaller bores (8–10 mm) use a 3×1.4 mm key; 10–12 mm bores use 4×1.8 mm; 14–17 mm bores use 5×2.3 mm; 18–22 mm bores use 6×2.8 mm; and 24–30 mm bores use 8×3.3 mm. Select the variant that matches your shaft's keyway slot.

Yes. The HTD-5M tooth profile and 5 mm pitch are internationally standardized. These pulleys are compatible with any HTD-5M synchronous belt with an 11 mm width, regardless of brand. Confirm your belt's pitch and width before ordering — do not mix HTD-5M pulleys with MXL, GT2, or other pitch belts.

45# medium-carbon steel has a tensile strength of approximately 600–700 MPa, roughly 3–4× that of common 6061 aluminum alloy. Steel pulleys are better suited for higher torque loads, heavier belts, and applications where the pulley bore is subject to significant clamping or keyway shear forces. The trade-off is added weight — steel pulleys are approximately 2.7× heavier than equivalent aluminum pulleys of the same size.

45# steel is not stainless and will oxidize in humid or wet environments without surface protection. For indoor workshop use, a light coat of machine oil or a dry-film lubricant on the bore and tooth faces is sufficient. For outdoor or high-humidity environments, consider applying a rust-inhibiting primer or selecting a stainless-steel or aluminum pulley instead.

Yes. HTD-5M pulleys are widely used in CNC routers, laser cutters, and larger-format 3D printers (particularly those using NEMA 23 or larger stepper motors). For compact desktop 3D printers using GT2 belts, verify that your printer uses HTD-5M and not GT2 (2 mm pitch) — the tooth profiles are not interchangeable despite looking similar.