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When a rigid coupling transmits every vibration and misalignment shock directly into your motor bearings, precision suffers and components wear prematurely. CNC builders, 3D printer enthusiasts, and machine tool operators who demand smooth, low-backlash power transmission need a coupling that absorbs the unexpected — without sacrificing torque capacity.
This flexible plum spider jaw coupling is machined from aluminum alloy hubs paired with a polyurethane (PU) spider insert. Available in three outer diameter families — Ø65 mm (≈2.56 in), Ø80 mm (≈3.15 in), and Ø95 mm (≈3.74 in) — with body lengths ranging from 90 mm to 130 mm (≈3.54–5.12 in). Bore sizes span 14 mm to 55 mm (≈0.55–2.17 in) depending on the selected variant, and both equal-bore and custom unequal-bore (d1≠d2) configurations are offered.
Ideal for CNC router Z-axis lead screw connections, stepper motor to ball screw couplings in 3D printers and laser engravers, and servo motor shaft connections in light industrial automation where angular and parallel misalignment compensation is required.
Lightweight yet rigid hub bodies machined for concentricity, reducing rotational imbalance at speed.
The PU spider element absorbs shock loads, dampens vibration, and compensates for angular and parallel shaft misalignment.
Outer diameters Ø65 / Ø80 / Ø95 mm with bore options from 14 mm up to 55 mm — covering the most common CNC and automation shaft sizes.
Four-jaw clamping hubs provide secure, backlash-minimizing grip on both shafts without requiring keyways.
Select the "d1≠d2, Leave a message" variant to specify two different bore diameters — ideal for motor-to-screw size mismatches.
Standard jaw coupling geometry fits most CNC controller and motor mount configurations without modification.
| Coupling Type | Flexible Plum Spider Jaw Coupling (4-Jaw Clamping) |
|---|---|
| Hub Material | Aluminum Alloy |
| Spider Insert Material | Polyurethane (PU) |
| Outer Diameter (D) | Ø65 mm / Ø80 mm / Ø95 mm — see variant options |
| Body Length (L) | 90 mm / 102 mm / 110 mm / 114 mm / 126 mm / 130 mm — see variant options |
| Bore Range (d1 / d2) | 14–38 mm (Ø65), 14–45 mm (Ø80), 18–55 mm (Ø95) — see variant options |
| Bore Configuration | Equal bore (d1=d2) or custom unequal bore (d1≠d2) |
| Finish | Natural anodized / machined aluminum |
| Quantity per Order | 1 piece (per variant selected) |
| Application | CNC routers, 3D printers, laser engravers, stepper/servo motor drives |
Match the outer diameter (Ø65, Ø80, or Ø95 mm) to your available mounting space and torque requirement — larger OD generally means higher torque capacity. Then select the bore option that matches your motor shaft diameter (d1) and lead/ball screw diameter (d2). If both shafts are the same size, choose an equal-bore variant (e.g., 20mm×20mm). If they differ, select "d1≠d2, Leave a message" and specify both diameters in your order notes.
Yes. The polyurethane spider insert is specifically designed to accommodate minor angular misalignment (typically up to ~1°) and small amounts of parallel (radial) offset between the two shafts. This protects motor bearings from side-loading caused by imperfect alignment during assembly. It is not intended for large misalignment — always align shafts as closely as possible for best performance and spider longevity.
Yes. The jaw coupling design allows the PU spider element to be replaced independently of the aluminum hubs. If the spider wears or hardens over time, you can source a replacement spider of the same jaw count and OD without replacing the entire coupling assembly.
Yes. NEMA 17 motors typically have 5 mm shafts and NEMA 23 motors commonly use 6.35 mm or 8 mm shafts — all of which fall within the bore range of the Ø65 mm variants (14–38 mm bore). For larger NEMA 34 motors with 12–14 mm shafts, the Ø65 mm or Ø80 mm variants are appropriate. Always confirm your specific motor shaft diameter before selecting a variant.
Aluminum alloy offers good natural corrosion resistance in typical indoor CNC and workshop environments. For applications exposed to coolant mist or high humidity, the anodized surface finish provides additional protection. Avoid prolonged exposure to strong acids or alkalis.
The body length (L) affects the axial distance between the two shaft ends inside the coupling. A longer body (e.g., L130 mm) provides more spider material between the jaws, which can improve vibration damping and accommodate slightly more axial float. A shorter body (e.g., L90 mm) is more compact and suitable for tight installations. Both share the same Ø80 mm outer diameter and bore range.
No keyway is required. The 4-jaw clamping hubs use set screws (grub screws) to clamp directly onto the shaft. Ensure the shaft surface is clean and free of burrs before tightening. For high-torque applications, a flat ground on the shaft (D-cut) is recommended to prevent rotation under load.
