A sheave quote is only as good as the specification behind it. Send a complete spec and you get a firm price and a part that drops onto the shaft first time; send a photo with “same as this” and you get questions, delays, or — worse — a wheel that almost fits.
This guide lists exactly what we need to machine a diverter or traction sheave to your requirement, in the order a machinist thinks about it.
Three ways to start
You don’t need a perfect drawing to get a quote. Any of these works:
- A drawing — PDF or DWG/DXF, even a hand sketch with dimensions. Fastest route to a firm quote.
- The old part — send the worn sheave (or lend it to us) and we measure and reproduce it, correcting for wear.
- A machine reference — machine model, rope size and count, and photos. We come back with the questions that pin the rest down.
The rest of this guide is what a complete specification contains — useful as a checklist whichever route you take.
The details that define a sheave
| Detail | What it controls | What to send |
|---|---|---|
| Outer diameter (OD) | Rope speed, fit in the machine space | Measured OD, or the drawing value |
| Groove profile | Traction and rope life | U / V / undercut, with angle and undercut width — or the machine model |
| Seat radius | Rope-to-groove fit | Your rope diameter; the seat is cut to suit |
| Number of grooves & pitch | Rope count and spacing | Groove count + centre-to-centre pitch |
| Rim width | Clearance in the machine | Overall width across the rim |
| Bore & fit | Mounting on the shaft | Shaft diameter and fit (H7 is typical), taper details if any |
| Keyway | Torque transmission | Key width × depth, or the shaft standard |
| Material | Strength, groove wear | Cast iron FG260, ductile SG500, EN8 — or tell us the duty and we advise |
| Hardness | Groove service life | If specified: hardness value and zone (groove faces) |
| Balancing / runout | Smooth, quiet running | Static balancing is standard; note a runout limit if your spec has one |
Two of these deserve a closer word.
Groove geometry is the specification
Everything else on the wheel is ordinary turning; the groove is where sheaves are won and lost. If you can, specify the profile explicitly — seat radius, groove angle, undercut width and depth, and the rope diameter it’s cut for. If you can’t, give us the machine model or the old sheave: the groove can be measured and matched. What we don’t recommend is guessing a profile from a catalogue photo — the difference between a 35° and 40° vee, or a narrow and wide undercut, is invisible in a picture and very visible in rope life.
Bore and keyway decide whether it fits
A sheave that’s perfect everywhere except the bore is scrap. Give the shaft diameter and the fit you need — H7 is the common bore tolerance for keyed lift-sheave mounting — plus the keyway dimensions or the standard your shaft follows. For taper-mounted sheaves, the taper angle and gauge dimension matter more than anything else on the print. If you’re unsure, a photo of the shaft end with a couple of vernier measurements answers it.
Tolerances: specify what matters
A good sheave drawing is tight where the part works and open where it doesn’t:
- Tolerance deliberately: bore fit, groove geometry, groove-to-groove pitch, and runout.
- Leave general: rim outside faces, hub outer surfaces, cosmetic chamfers — general machining tolerance is fine there.
Our lathes hold up to ±0.02 mm where the drawing calls for it — see the custom machining capabilities — but tolerance costs money wherever it’s printed, so spend it on the working surfaces.
What a complete enquiry looks like
Copy this into an email, the quote form or WhatsApp and fill in what you know:
- Part type: diverter / traction / pulley, and quantity
- OD, rim width, groove count and pitch
- Rope diameter and groove profile (or machine model / old part available)
- Bore, fit and keyway (or shaft details)
- Material and any hardness requirement
- Drawing attached (PDF/DWG/DXF) — or photos of the old part with measurements
Half the list is still enough to start. Send it through the quote form with your drawing attached, and we’ll reply with a price, the lead time, and whatever questions remain.
Common questions
I don't have a drawing — can you still make the sheave?
Yes. Send the worn sheave or a sample and we reverse-engineer it — outer diameter, groove geometry, pitch, bore and keyway are all measurable from the part. A machine model or nameplate photo helps us cross-check what we measure.
Which file formats do you accept?
PDF and DWG/DXF drawings are ideal. A clear photo or scan of a dimensioned sketch works too — the quote form takes PDF, DWG/DXF or images up to 5 MB, and you can send the same files on WhatsApp.
Do I need to specify a tolerance on every dimension?
No — and please don't. Tolerance the surfaces that matter: the bore fit, the groove geometry and the runout. Blanket tight tolerances on non-working surfaces only add machining time and cost without improving the part.