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When shaft misalignment causes vibration, noise, or premature wear in your CNC router, stepper motor drive, or 3D printer, the root cause is often a rigid coupling that cannot compensate for angular or parallel offset. This flexible plum coupling is engineered for builders, machinists, and repair technicians who need a reliable, zero-backlash connection between two shafts of equal or different diameters.
Each coupler features an aluminum alloy body (D45mm outer diameter) paired with a polyurethane spider insert that absorbs shock and dampens vibration. Two body lengths are available — L66mm (~2.60 in) and L78mm (~3.07 in) — with dual-bore hole combinations ranging from 6mm×6mm up to 25mm×25mm (approximately 0.24 in to 0.98 in per bore). The spider insert fits between the two jaw halves, providing flexible plum coupling performance without metal-to-metal contact.
Typical use cases include CNC stepper motor shaft coupling for lead-screw drives, 3D printer Z-axis flexible coupler replacement, servo motor shaft connector for light-duty automation, and DIY lathe or milling machine flexible shaft adapter projects.
Available in same-diameter and stepped-bore combinations (e.g., 6×6mm through 25×25mm), letting you connect shafts of different sizes without adapters.
The plum-shaped elastomer spider absorbs shock loads and dampens torsional vibration, protecting motors and lead screws from impact damage.
Choose D45×L66mm (~2.60 in) for compact builds or D45×L78mm (~3.07 in) where additional flex travel or clearance is needed.
The jaw-and-spider design maintains consistent angular positioning, critical for CNC stepper motor shaft coupling and 3D printer Z-axis accuracy.
Lightweight yet rigid aluminum jaws resist corrosion and handle continuous rotational loads typical of stepper and servo motor applications.
Each bore is secured with set screws for tool-free shaft changes during prototyping or maintenance — no press-fit required.
| Outer Diameter (D) | 45mm (~1.77 in) |
|---|---|
| Body Length (L) | 66mm (~2.60 in) or 78mm (~3.07 in) — see variant options |
| Bore Hole Combination (d1 × d2) | 6mm×6mm to 25mm×25mm — see variant options |
| Body Material | Aluminum alloy |
| Spider Insert Material | Polyurethane (PU) |
| Coupling Type | Jaw / Plum (spider) flexible coupling |
| Clamping Method | Set screw |
| Finish | See variant options |
| Max Recommended Speed | See variant options |
| Quantity per Order | 1 piece |
Measure the shaft diameter of your motor (d1) and the shaft or lead screw it connects to (d2). Select the matching d1×d2 option from the dropdown. If both shafts are the same size, choose an equal-bore variant such as 8mm×8mm. If they differ, choose the stepped option, e.g., 6mm×8mm.
The L66 (66mm / ~2.60 in) version is suited for compact CNC and 3D printer frames where axial space is limited. The L78 (78mm / ~3.07 in) version provides slightly more spider travel and is preferred when greater angular misalignment compensation or additional clearance between motor face and lead screw nut is needed.
Yes. The polyurethane spider insert accommodates minor angular misalignment (typically up to ~1°) and small parallel offsets. For best results, align shafts as closely as possible before installation — the coupler is designed to compensate for residual misalignment, not replace proper alignment.
Yes. The two aluminum jaw halves separate to allow the spider insert to be swapped without removing the coupler from the shafts. This makes maintenance straightforward in production or workshop environments.
NEMA 17 motors typically have a 5mm shaft, and NEMA 23 motors commonly use 6.35mm (1/4 in) or 8mm shafts. Check your motor's shaft diameter and select the matching bore option. The D45 outer diameter fits standard CNC and 3D printer frame clearances for both motor sizes.
Each jaw half is secured with set screws. Insert the shaft into the bore until it reaches the correct depth, then tighten the set screw with an appropriate hex key. For high-torque applications, apply a small amount of thread-locking compound to the set screw threads to prevent loosening from vibration.
Rated torque depends on bore size and operating speed. For typical CNC stepper motor and 3D printer Z-axis applications the transmitted torque is well within the coupler's capacity. Contact us to confirm specifications for high-torque or high-speed servo applications.
