Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
When misalignment, vibration, or shaft runout causes premature wear on your CNC machine, pump, or motor drivetrain, the coupling is often the first component to fail. Engineers, machinists, and DIY builders who demand reliable torque transmission without rigid metal-to-metal contact need a coupling that absorbs shock while maintaining rotational accuracy. This 30mm spider jaw plum coupler is engineered for exactly that application.
Each coupling consists of two aluminum alloy hubs and a polyurethane spider insert (plum element). The body diameter is 30mm (approximately 1.18 inches), available in two lengths — L35mm (~1.38 in) and L42mm (~1.65 in). Bore combinations (φd1 × φd2) range from 5mm × 5mm up to 16mm × 16mm, covering the most common shaft pairings in metric CNC and automation setups. Available in 1-piece or 5-piece quantities.
Typical use cases include CNC router Z-axis and lead screw connections, stepper motor to ball screw couplings for 3D printers and engravers, pump shaft connections in fluid handling systems, and servo motor output shaft couplings in light industrial automation. Long-tail applications include flexible jaw coupling for NEMA 23 stepper, spider coupler for 8mm to 10mm shaft, and aluminum plum coupler for CNC ballscrew.
| Body Diameter (D) | 30mm (~1.18 in) |
|---|---|
| Body Length (L) | 35mm (~1.38 in) or 42mm (~1.65 in) — see variant options |
| Bore Diameter φd1 × φd2 | 5mm–16mm × 5mm–16mm — see variant options |
| Hub Material | Aluminum alloy |
| Spider Insert Material | Polyurethane (PU) |
| Coupling Type | Spider jaw / plum / three-jaw flexible |
| Finish | Natural anodized aluminum |
| Quantity per Pack | 1 Pcs or 5 Pcs — see variant options |
| Torque Capacity | See variant options |
| Max RPM | See variant options |
| Misalignment Tolerance | Angular: typically ±1°; Parallel: typically 0.2–0.5mm |
Measure the shaft diameters on both the driving side (motor/pump) and the driven side (lead screw/encoder). Select the φd1 × φd2 option that matches those two diameters. If both shafts are the same size, choose a matching pair such as 8mm × 8mm. Use the variant selector above to find your combination.
The L35mm version is more compact and suited for tight installations where axial space is limited. The L42mm version provides a longer spider element engagement zone, which can offer slightly greater flexibility and vibration damping. Both share the same 30mm outer diameter and bore range.
Yes. The polyurethane spider insert accommodates angular misalignment of typically ±1° and parallel (radial) misalignment of approximately 0.2–0.5mm. It also handles minor axial displacement. For best results, align shafts as closely as possible — the coupling compensates for residual misalignment, not gross misalignment.
Yes. Spider jaw couplings are widely used in CNC routers, laser cutters, and 3D printers to connect NEMA 17 or NEMA 23 stepper motors to lead screws or ball screws. The flexible insert reduces backlash transmission and absorbs motor cogging vibration, improving positioning accuracy.
Aluminum alloy has natural corrosion resistance due to its oxide layer. In typical indoor workshop conditions — including exposure to cutting fluids and light moisture — these hubs perform reliably. For highly corrosive or submerged environments, additional protective measures may be needed.
Each hub features a clamping screw (set screw) that locks onto the shaft. Slide each hub onto its respective shaft, align the spider insert between the two hubs, and tighten the set screws to the manufacturer's recommended torque. Ensure the spider element is fully seated in the jaw slots before final tightening. No special tools beyond a hex key are required.
Yes. The polyurethane spider insert is a separate component that sits between the two hubs. If the insert wears or degrades over time, you can replace it independently without replacing the aluminum hubs, reducing maintenance cost. Contact us to confirm insert availability for your specific coupling size.
