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When shaft misalignment, vibration, or angular offset causes premature wear on your CNC machine, 3D printer, or stepper motor drive system, the weak link is almost always the coupling. Engineers, makers, and automation builders who demand reliable torque transmission without sacrificing flexibility need a coupling that can handle real-world imperfections — and that's exactly what this flexible plum spider jaw shaft coupler is designed to do.
Each coupler consists of two aluminum alloy hubs and a polyurethane (PU) spider insert. The hubs are precision-machined from 6061-T6 aluminum alloy with a natural anodized finish, offering a lightweight yet rigid structure. The PU spider element sits between the jaws of both hubs, absorbing shock and compensating for parallel, angular, and axial misalignment. Available in coupler body diameters from 14mm to 105mm (0.55" to 4.13") and lengths from 22mm to 140mm (0.87" to 5.51"), with bore shaft diameter ranges from 3mm to 60mm (0.12" to 2.36") depending on the selected variant.
Typical use cases include CNC router Z-axis and lead screw connections, NEMA 17/23/34 stepper motor shaft coupling for 3D printers and laser engravers, servo motor coupling in pick-and-place automation systems, and flexible shaft coupling for DIY robotics and linear actuator assemblies.
Three-jaw interlocking hub geometry maximizes torque transfer while the PU spider insert absorbs shock loads and dampens vibration between connected shafts.
22 variants spanning coupler OD from 14mm to 105mm and shaft bore from 3mm to 60mm — covering NEMA 17 through large-frame servo motor applications in a single product line.
Accommodates parallel misalignment up to typically 0.2–0.5mm, angular misalignment up to typically 1°–3°, and axial float, reducing bearing load and extending drivetrain life.
Precision-machined 6061-T6 aluminum hubs deliver a high strength-to-weight ratio, corrosion resistance, and dimensional stability across a wide operating temperature range.
Each hub is secured to the shaft via set screws, enabling tool-free shaft swaps and quick repositioning without permanent modification to the motor or lead screw shaft.
The polyurethane spider insert provides electrical isolation between the two hubs, protecting sensitive motor encoders and control electronics from ground loop interference.
| Coupler Body Diameter (OD) | 14mm – 105mm (0.55" – 4.13") |
|---|---|
| Coupler Body Length | 22mm – 140mm (0.87" – 5.51") |
| Shaft Bore Diameter Range | 3mm – 60mm (0.12" – 2.36") — See variant options |
| Hub Material | 6061-T6 Aluminum Alloy |
| Spider Insert Material | Polyurethane (PU) |
| Surface Finish | Natural Anodized |
| Coupling Type | Flexible Jaw / Plum Spider |
| Fastening Method | Set Screw |
| Misalignment Tolerance (Parallel) | Typically 0.2–0.5mm |
| Misalignment Tolerance (Angular) | Typically 1°–3° |
| Operating Temperature | Typically –30°C to +100°C |
| Weight | See variant options |
| Number of Variants | 22 sizes |
Match the coupler's shaft bore range to your motor shaft diameter and lead screw diameter. For example, a NEMA 17 stepper typically has a 5mm shaft — select a variant whose shaft bore range includes 5mm (e.g., D14mm x L22mm, bore 3–8mm). The coupler OD and length should fit within your motor mount clearance.
The bore is sized for metric shafts. Imperial shafts that fall within the listed bore range (e.g., 1/4" ≈ 6.35mm) can typically be accommodated, but verify the exact bore diameter of the selected variant against your shaft's imperial measurement before ordering.
The polyurethane spider insert is rated for moderate-to-high torque transmission suitable for CNC lead screws, 3D printer axes, and light servo applications. Exact torque ratings vary by coupler size — larger diameter couplers (D40mm and above) handle significantly higher torque loads than smaller variants.
The anodized 6061-T6 aluminum hubs offer good corrosion resistance for indoor and moderately humid environments. The anodizing layer protects against oxidation. For prolonged outdoor or salt-spray exposure, additional protective coating is recommended.
Yes. The flexible jaw design is compatible with stepper motors (NEMA 17, 23, 34) and servo motors, provided the shaft diameter falls within the selected variant's bore range. The PU spider also helps dampen the torque ripple characteristic of stepper motors, reducing resonance in the drivetrain.
Each variant lists two bore values — one for each hub. For example, "3mm to 8mm" means one hub is bored to 3mm and the other to 8mm, allowing you to connect two shafts of different diameters. If you need both ends the same size, select a variant where both values match your shaft diameter, or contact us to confirm bore configuration.
The PU spider insert is a wear component and can typically be replaced independently of the aluminum hubs. If the spider shows cracking or deformation from overload, replacing only the insert restores coupling performance without replacing the entire assembly.
