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When a rigid connection between your motor shaft and lead screw causes vibration, binding, or premature wear, a flexible shaft coupling is the fix. Designed for CNC builders, 3D printer enthusiasts, and automation engineers who need a forgiving yet firm connection between a stepper motor and a driven shaft, this nylon plastic flexible shaft coupling absorbs minor angular and parallel misalignment without transmitting shock loads back to the motor bearings.
Each coupling is machined from engineering-grade nylon, offering a lightweight yet durable alternative to all-metal jaw couplings. Available in three OD×Length×Bore configurations — 13×22mm (bore 4–4mm), 15×22mm (bore 6–6mm), and 18×25mm (bore 8–8mm) — covering shaft diameters from approximately 4mm (0.16 in) to 8mm (0.31 in) with outer diameters from 13mm (0.51 in) to 18mm (0.71 in).
Typical applications include NEMA 17 and NEMA 23 stepper motor drives on CNC routers, RepRap-style 3D printers, laser engravers, and small linear actuator assemblies where a nylon flexible coupler for lead screw connections reduces resonance and noise during rapid direction changes.
Helical-cut or spider-style nylon body absorbs angular and parallel shaft misalignment, reducing vibration transmitted to motor bearings.
Engineering-grade nylon body keeps rotational inertia low — ideal for high-speed direction reversals in CNC and 3D printing applications.
Choose from 4mm, 6mm, or 8mm bore diameters (both ends matched) to suit your specific motor shaft and lead screw combination.
Grub screws on each hub clamp firmly to the shaft, providing a secure, slip-resistant connection without permanent modification to the shaft.
Nylon material naturally dampens resonance, resulting in quieter operation compared to rigid aluminum couplings during stepper motor micro-stepping.
Available in 1, 3, or 5-piece packs — stock up for multi-axis machines or keep spares on hand for maintenance without overpaying per unit.
| Material | Engineering-grade nylon (PA) |
|---|---|
| Outer Diameter (OD) | 13mm / 15mm / 18mm (see variant options) |
| Length (L) | 22mm / 22mm / 25mm (see variant options) |
| Bore Diameter | 4mm / 6mm / 8mm (both ends matched, see variant options) |
| Shaft Clamping | Set screw (grub screw) |
| Coupling Type | Flexible / Spider-type |
| Max Recommended RPM | See variant options |
| Finish | Natural nylon (off-white / beige) |
| Pack Quantity | 1 Pcs / 3 Pcs / 5 Pcs (see variant options) |
| Compatible Motor Types | NEMA 17, NEMA 23 stepper motors |
Measure your motor output shaft diameter and your lead screw or driven shaft diameter. Both ends of this coupling share the same bore size (e.g., 4–4mm, 6–6mm, 8–8mm), so both shafts must match the selected bore. Common NEMA 17 motors use a 5mm shaft — if your motor is 5mm, this coupling is not the right fit; select a 5mm bore variant instead. NEMA 23 motors typically use 6.35mm or 8mm shafts.
Yes. The flexible nylon body accommodates minor angular misalignment (typically up to 1–3°) and small amounts of parallel offset. It is not designed for large misalignment — always align your motor and lead screw as closely as possible during installation to maximize coupling lifespan and minimize vibration.
Engineering-grade nylon (PA) offers a good balance of tensile strength, flexibility, and low rotational inertia for light-to-medium duty CNC and 3D printing applications. For heavy-duty industrial CNC machines with high torque requirements, a metal jaw coupling may be more appropriate. For standard desktop CNC routers and FDM 3D printers, nylon couplings are widely used and perform reliably.
Nylon is inherently resistant to oils, greases, and mild chemicals, making it suitable for workshop environments. It does not rust. However, prolonged exposure to UV light or very high temperatures (above approximately 100°C / 212°F) may cause gradual degradation. For standard indoor CNC and 3D printing use, longevity is not a concern under normal operating conditions.
The outer diameter (OD) reflects the physical size of the coupling body. Larger OD couplings (15mm, 18mm) are paired with larger bore sizes (6mm, 8mm) and can generally handle slightly higher torque loads. Choose based on your shaft diameter first — the OD is a consequence of the bore size, not a separate selection. Ensure your machine frame has clearance for the selected OD before ordering.
For a single-axis machine (e.g., a simple Z-axis upgrade), 1 piece is sufficient. For a 3-axis CNC router or CoreXY 3D printer, ordering a 3-pack or 5-pack provides spares for future maintenance and is more cost-effective per unit. Multi-pack options are available directly from the variant selector above.
Insert the motor shaft into one end of the coupling and the lead screw into the other end, ensuring each shaft is fully seated to the depth of the bore. Use an appropriate hex key (Allen wrench) to tighten the grub screws firmly against the flat or round section of each shaft. Avoid over-tightening, which can crack the nylon hub. Check tightness after the first few hours of operation as set screws can loosen slightly during initial break-in.
