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When misalignment, vibration, or bore-size mismatch causes premature wear on your CNC spindle or motor drive, the right flexible coupling makes all the difference. Engineers, machine builders, and DIY CNC enthusiasts who need a reliable, zero-backlash connection between shafts of different diameters will find this D45mm spider jaw plum coupler a direct solution.
This coupling set consists of two aluminum alloy hubs and a polyurethane spider insert. The outer diameter is 45mm (approximately 1.77 in), available in body lengths of 75mm (~2.95 in) and 85mm (~3.35 in). Bore combinations span φd1 and φd2 from 14mm to 25mm (approximately 0.55 in to 0.98 in), covering same-bore and stepped-bore configurations.
Typical applications include CNC router Z-axis drives using spider jaw flexible couplings, servo motor to ballscrew connections requiring D45 plum couplers, and stepper motor shaft adapters for 3D printer or laser engraver builds where vibration damping is critical.
Machined aluminum alloy hubs deliver low rotational inertia and corrosion resistance, keeping your drive train responsive and long-lasting.
The six-jaw polyurethane spider absorbs shock and vibration between hubs, protecting sensitive encoders and ballscrews from impact loads.
Bore combinations from 14mm × 14mm up to 25mm × 25mm — including stepped-bore variants — accommodate a broad range of motor and shaft pairings without adapters.
Choose L75mm for compact installations or L85mm where additional axial clearance is needed between motor face and driven component.
The spider jaw (plum) geometry maintains consistent torque transmission without rotational play, critical for closed-loop CNC positioning accuracy.
Order one coupling for a single axis or a 5-piece pack for multi-axis builds and spare inventory — both options available for every bore combination.
| Outer Diameter (D) | 45mm (~1.77 in) |
|---|---|
| Body Length (L) | 75mm (~2.95 in) or 85mm (~3.35 in) — see variant options |
| Bore Diameter (φd1 × φd2) | 14mm–25mm × 14mm–25mm — see variant options |
| Hub Material | Aluminum alloy |
| Spider Insert Material | Polyurethane (PU) |
| Coupling Type | Spider jaw / plum / flexible jaw |
| Bore Configuration | Same-bore and stepped-bore available |
| Quantity per Order | 1 Pcs or 5 Pcs — see variant options |
| Finish | Natural anodized aluminum |
| Typical Torque Capacity | Contact us to confirm |
| Max RPM | Contact us to confirm |
Select L75mm when you need a compact coupling with minimal axial space between the motor face and the driven shaft (such as a ballscrew nut housing). Choose L85mm when you need extra clearance — for example, when a motor flange protrudes or when you need more room to tighten the clamping screws on both hubs without interference.
φd1 is the bore diameter of one hub (typically the motor shaft side) and φd2 is the bore diameter of the other hub (typically the ballscrew or driven shaft side). Measure both shaft diameters with a caliper and select the matching combination. If both shafts are the same size — for example, both 20mm — choose the 20mm × 20mm option. If they differ, choose the stepped-bore variant that matches both.
The spider jaw design minimizes rotational play between hubs when the polyurethane insert is properly seated and the clamping screws are torqued correctly. For most CNC routing, laser engraving, and 3D printing applications this provides functionally zero backlash. For ultra-precision servo systems with sub-micron positioning requirements, verify the specific backlash rating with us before ordering.
Yes. The polyurethane spider insert sits between the two aluminum hubs and can be removed and replaced independently. This is useful when the insert shows wear or hardening after extended use in high-temperature or high-cycle environments, allowing you to extend the life of the aluminum hubs.
The flexible spider jaw design accommodates small degrees of angular misalignment (typically up to 1°–3°) and minor parallel offset between shafts. It is not intended to compensate for large misalignment — always align your motor and driven shaft as accurately as possible during installation to maximize coupling life and positioning accuracy.
A rigid coupling transmits torque with no flex, which means any shaft misalignment creates bearing stress and vibration. A spider jaw (plum) coupling uses a flexible polyurethane insert to absorb vibration and tolerate small misalignment, making it the preferred choice for servo and stepper motor drives where protecting the motor bearings and encoder is important.
The bore sizes listed are metric (mm). If your shaft is imperial, convert the diameter to millimeters and select the closest available bore. For example, a 5/8 in shaft is approximately 15.875mm — in this case, contact us to confirm fit before ordering, as the bore tolerance may or may not accommodate a press or slip fit on an imperial shaft.
