The Profile Has to Match the Belt
A pulley only works if its groove or tooth profile matches the belt and its pitch diameter gives the right ratio. Off-the-shelf pulleys come in fixed bores and tooth counts, so a custom shaft size, an unusual ratio, or a discontinued part means machining one. For a timing pulley the tooth form is a standard profile (HTD, GT2, T5, MXL…), so we reproduce it precisely; for a V-belt pulley the groove angle and depth match the belt section.
Custom Pulley Specifications
| Attribute | Capability |
|---|---|
| Types | Timing (toothed), V-belt, flat, idler |
| Timing profiles | HTD 3M/5M/8M, GT2, T5/T10, MXL, XL |
| Materials | 6061 aluminium, steel, stainless |
| Bore | Plain, keyed (DIN 6885), set-screw, taper bush |
| Flanges | One or both sides to retain the belt |
| Quantity | One-off to batch |
Belt Profiles & Pitch Diameter — How to Identify Your Pulley
A timing pulley is defined by its belt profile (tooth shape) and pitch (tooth-to-tooth spacing). Match those and the tooth count, and the pulley meshes correctly. The common profiles and pitches:
| Profile | Pitches | Notes |
|---|---|---|
| GT2 / GT3 (PowerGrip) | 2, 3, 5, 8, 14 mm | Higher load, low backlash, quiet — modern standard |
| HTD | 3M, 5M, 8M, 14M | Rounded teeth; more backlash than GT2, high power |
| T / AT (metric trapezoidal) | T2.5, T5, T10 / AT5, AT10 | Positioning, linear drives |
| MXL / XL / L (imperial) | 0.080" / 0.200" / 0.375" | Older imperial trapezoidal |
The pitch diameter follows directly from the tooth count and belt pitch: PD = N × p ÷ π (N = teeth, p = belt pitch). So if you know the belt and count the pulley's teeth, the pulley is fully specified — which is exactly how we reproduce one from a sample. Note GT2 and HTD of the same pitch number are not interchangeable (different tooth shape), so tell us the exact profile or send the belt.
How We Make / Reproduce a Pulley
- From specs: give us belt profile, tooth count or pitch diameter, width and shaft size.
- From a sample: we measure the profile, OD, width, bore and keyway and rebuild it — see reverse engineering.
- Bore to fit: keyway, set-screw flats or taper bore to your shaft and drive.
Material Choice
Aluminium keeps a pulley light and low-inertia (anodized for wear); steel or stainless for high torque or harsh environments. Light-duty pulleys can also run in Delrin/nylon. Bore and profile are verified on inspection.
Discontinued pulley, no drawing? Send the worn pulley (and the belt if you can) and we reproduce it with the correct profile and shaft fit — one or a batch. No drawing required.
Frequently Asked Questions
Yes — tell us the belt profile (HTD/GT2/T5/MXL) and tooth count, or send the belt and old pulley, and we machine the correct tooth form, pitch diameter, bore and keyway, with flanges if needed.
Yes — we measure profile, OD, width, bore and keyway and rebuild it. Timing profiles are standard, so even a worn pulley yields a correct new one.
Timing, V-belt and flat pulleys plus idlers, in aluminium, steel and stainless, with plain, keyed or taper bores.
All available — keyway to DIN 6885, set-screw flats, or taper-lock bush bore to your shaft.
Quote a Custom Pulley
Belt profile, sample or drawing — all accepted. Reply in 24h.