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When your CNC router, 3D printer, or automated conveyor demands slip-free, repeatable motion, a poorly fitted pulley becomes the weakest link in the entire drive train. Engineers and serious makers who need dimensional accuracy and long service life turn to L type 25mm timing belt drive pulleys machined from solid 45 steel — a material that delivers the toughness and machinability required for demanding duty cycles.
Each pulley is machined from 45 carbon steel and features the standard L-pitch tooth profile (25.4 mm / 1 inch pitch) with a smooth, flat tooth face designed to mate with L-type timing belts. Tooth counts span 20 T through 40 T (see variant options for the full range), and bore diameters run from 8 mm (0.31 in) to 28 mm (1.10 in). Keyway options include without keyway, 3 mm, 4 mm, 5 mm, 6 mm, and 8 mm widths to suit standard shaft keyway standards.
Typical use cases include CNC router X/Y axis drives requiring consistent belt engagement, 3D printer extruder and gantry drive systems where tooth-skip causes print failures, and light industrial conveyor or indexing table drives where a keyed bore ensures zero rotational slip under sustained load.
| Belt Type | L (25.4 mm / 1 inch pitch) |
|---|---|
| Belt Width Compatibility | 25 mm (1 inch) — standard L-series |
| Tooth Count | See variant options (20 T – 40 T range) |
| Bore Diameter | See variant options (8 – 28 mm) |
| Keyway Width | See variant options (without keyway / 3 / 4 / 5 / 6 / 8 mm) |
| Material | 45 Carbon Steel |
| Tooth Profile | L-type, smooth tooth face (no flange) |
| Pitch Diameter | See variant options |
| Surface Finish | Machined (natural steel) |
| Quantity | 1 piece per order |
The tooth count determines your drive ratio. Divide the driven pulley teeth by the driver pulley teeth to get the ratio. For example, a 20 T driver paired with a 40 T driven pulley gives a 2:1 reduction. Higher tooth counts on the driver increase output speed; lower tooth counts increase torque. Match the tooth count to your required speed and torque output, and ensure the belt length accommodates the center distance between pulleys.
Keyway width is determined by your shaft diameter and the applicable standard (DIN 6885 / ISO 773). Common pairings: 8–10 mm shaft → 3 mm keyway; 10–12 mm shaft → 4 mm keyway; 12–17 mm shaft → 5 mm keyway; 17–22 mm shaft → 6 mm keyway; 22–30 mm shaft → 8 mm keyway. If your shaft has no keyway slot, select "without keyway" and secure with a set screw or interference fit.
45 carbon steel has a typical tensile strength of approximately 600–800 MPa in the normalized condition, making it well-suited for moderate-to-high belt tension applications such as CNC gantries, 3D printer drives, and light conveyor systems. For extremely high-load or corrosive environments, consider whether a surface treatment or alternative material is needed for your specific duty cycle.
45 carbon steel is not inherently corrosion-resistant. In dry indoor environments (CNC workshops, 3D printing labs), surface oxidation is minimal with normal use. For humid or outdoor environments, applying a light machine oil or clear lacquer to exposed surfaces will significantly extend service life. If corrosion resistance is a primary requirement, consider stainless steel or aluminum pulleys instead.
These pulleys are designed for standard L-pitch timing belts with a 25.4 mm (1 inch) tooth pitch and a belt width of 25 mm (1 inch). Confirm your belt pitch and width before ordering. Do not use with XL, T5, T10, GT2, or other pitch standards — the tooth geometry will not mesh correctly.
Yes. The "without keyway" variants are designed for set-screw mounting. Drill and tap a radial set screw hole in the hub if not already present, and use a hardened-tip set screw against a flat on the shaft for best holding force. This method is suitable for light-to-moderate torque applications. For high-torque or reversing loads, a keyed bore provides significantly more reliable torque transmission.
Measure your shaft diameter with a digital caliper to the nearest 0.1 mm. Select the bore size that matches your shaft diameter exactly — these pulleys are machined to close tolerances for a slip or light interference fit. Do not select a bore smaller than your shaft diameter.
