Couplings Live or Die on Concentricity
A shaft coupling joins two shafts and transmits torque between them. Its critical requirements are clear: bores sized to fit each shaft (often with a keyway or clamp), and those bores concentric to each other so the joined shafts run true without vibration. Add the torque-transmitting feature — keyway, set screw, clamp slot or flange bolts — and you have a coupling. We machine the body around those exact requirements.
Custom Coupling Specifications
| Attribute | Capability |
|---|---|
| Materials | 1045 / 4140 steel, 304/316 stainless, aluminium — plus acetal/Delrin for light-duty |
| Bores | Two ends, each to fit its shaft (slip / transition / interference) |
| Concentricity | Bores machined concentric, low runout |
| Torque feature | Keyway, set screw, clamp slot, or flange bolts |
| Tolerance | Bores ±0.01–0.02 mm; keyway to DIN 6885 / ISO 773 |
| Quantity | One-off to batch |
Rigid or Flexible? How to Choose
The first decision on any coupling is rigid vs flexible — it comes down to whether your two shafts are perfectly aligned, and whether the drive needs to absorb misalignment, shock or backlash:
| Rigid coupling | Flexible coupling | |
|---|---|---|
| Shaft alignment needed | Near-perfect | Tolerates misalignment |
| Misalignment absorbed | None | Axial · parallel · angular |
| Torque transfer | Maximum | High (type-dependent) |
| Backlash | Zero (solid) | Zero/low types for servo & motion control |
| Vibration damping | None | Yes (elastomer / spring types) |
| Best for | Aligned shafts, max torque | Motors, gearboxes, robotics, automation |
Not sure? Tell us the two shaft sizes, the torque, and whether there's any misalignment, and we'll recommend the right type.
Coupling Types We Machine — Compared
Once rigid vs flexible is settled, the type sets how much misalignment and backlash the drive can take. This is the side-by-side most catalogue pages don't give you:
| Type | Misalignment handled | Backlash | Best for |
|---|---|---|---|
| Rigid sleeve (set-screw / clamp) | None — needs alignment | Zero | Aligned shafts, max torque, encoders |
| Clamp / split | None | Zero | Grip without marring; easy install |
| Flanged (bolted halves) | None | Zero | High-torque bolted drives |
| Step / reducer | None | Zero | Joining two different shaft sizes |
| Beam / helical (1-piece) | Small angular · parallel · axial | Low / near-zero | Servo & motion control, light torque |
| Oldham | Parallel offset | Low | Parallel-misaligned shafts, damping |
| Jaw hub (+ elastomer spider) | Angular · parallel + damping | Low (spider-dependent) | Motor↔pump, vibration, general drive |
We machine the metal body of any of these; on jaw couplings the elastomer spider is a standard item we help you source.
Material & Fit
For torque transmission we usually machine couplings in 4140 or 1045 steel, stainless for corrosion, or aluminium for light duty. Bores are cut to the fit each shaft needs and kept concentric in a controlled setup; keyways are matched to the shaft standard. Runout is verified on inspection.
Broken or discontinued coupling? Even one cracked clean through can be rebuilt — we reverse-engineer the bores, keyway and length. See our real case: reverse-engineered drive-shaft coupling. No drawing needed.
Frequently Asked Questions
Yes. Tell us the two shaft diameters (and keyways) and we bore each end to the right fit, concentric to each other so the shafts run true. Different sizes on each end are fine.
Yes — even cracked through. We measure and rebuild bores, keyways, set-screw/clamp holes and length. See our reverse-engineered drive-shaft coupling case. No drawing required.
Rigid sleeve, clamp/split, flanged, set-screw, step/reducer, and jaw coupling hubs. We machine the metal body; the elastomer spider of flexible jaw couplings is sourced separately.
4140/1045 steel for torque, stainless for corrosion, aluminium for light duty. We bore both ends and turn the outside in a controlled setup for concentric bores and low runout.
Quote a Custom Coupling
Shaft sizes, drawing or sample — all accepted. Reply in 24h.
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