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When misalignment, vibration, or shaft runout threatens the accuracy of your CNC machine, 3D printer, or motor-driven assembly, a rigid coupling simply won't cut it. Engineers, makers, and machine builders who demand reliable torque transmission without sacrificing flexibility turn to the flexible plum spider jaw shaft coupler — a go-to solution for precision motion systems where zero-backlash performance and vibration damping are non-negotiable.
Each coupler is machined from aluminum alloy and consists of two jaw hubs paired with a polyurethane spider insert. Available in outer diameters from 20mm to 105mm (~0.79" to ~4.13") and lengths from 25mm to 140mm (~0.98" to ~5.51"), with bore sizes ranging from 4mm to 62mm to suit a wide variety of shaft diameters. Select your exact OD × Length and bore size combination from the variant options above.
Typical applications include CNC router spindle-to-motor connections, stepper and servo motor shaft couplings for 3D printers and laser engravers, lead screw couplings in linear motion systems, and light-duty pump or conveyor drive connections where angular and parallel misalignment compensation is required.
Machined aluminum alloy construction delivers a strong, lightweight hub body that resists corrosion and handles the torque demands of CNC and motor-driven applications.
The flexible spider (plum) insert absorbs shock loads and dampens vibration between hubs, protecting sensitive encoders, bearings, and lead screws from impact damage.
Twenty-one OD × Length combinations and bore sizes from 4mm to 62mm cover the majority of metric stepper, servo, and spindle shaft diameters used in DIY and light industrial builds.
The jaw-and-spider design accommodates angular misalignment (typically up to ~1°) and parallel offset, reducing stress on motor bearings and extending drivetrain service life.
Each hub is secured to the shaft via set screws, allowing tool-free disassembly and re-use when reconfiguring your machine or swapping motors.
The interference fit between jaw hubs and spider insert minimizes rotational play, making these couplers well-suited for position-critical CNC axes and closed-loop servo systems.
| Material (Hubs) | Aluminum Alloy |
|---|---|
| Spider Insert Material | Polyurethane (PU) |
| Outer Diameter (OD) Range | 20mm – 105mm (0.79" – 4.13") |
| Length Range | 25mm – 140mm (0.98" – 5.51") |
| Bore Size Range | 4mm – 62mm (see variant options) |
| Bore Fixing Method | Set Screw (Grub Screw) |
| Coupling Type | Flexible Jaw / Plum Spider |
| Finish | See variant options |
| Quantity per Order | 1 Pcs / 2 Pcs / 5 Pcs (see variant options) |
| Weight | See variant options |
First, measure your motor shaft diameter and lead screw or spindle shaft diameter — these are your bore sizes. Then select an OD that provides enough hub wall thickness for your torque load (larger OD = more torque capacity). Use the variant dropdowns to match your exact bore size range. If your two shafts differ in diameter, both bore sizes must fall within the selected variant's bore range.
Yes. The flexible polyurethane spider insert allows the jaw coupler to compensate for angular misalignment (typically up to ~1°) and small amounts of parallel offset between shafts. It is not designed for large axial displacement — keep shaft end gaps within a few millimeters for best performance.
Aluminum alloy naturally forms a protective oxide layer that resists light corrosion in typical workshop and indoor environments. For outdoor or high-humidity applications, consider applying a light coating of machine oil to the hub surface. The polyurethane spider insert is also resistant to oils and mild chemicals.
These couplers are sized in metric bore dimensions. Imperial shaft sizes can often be accommodated if the inch diameter converts to a value within the listed bore range (e.g., a 1/4" shaft ≈ 6.35mm would fit within a 6mm–16mm bore variant). Always verify the converted bore diameter falls within the selected variant's range before ordering.
Each hub is fixed to the shaft using set screws (grub screws) tightened with a hex key. Ensure the set screw contacts a flat on the shaft (if present) for maximum holding force. Torque the set screws to the manufacturer's recommended value for your shaft diameter to avoid slippage under load.
Each "Pcs" quantity refers to the number of complete coupler assemblies (two hubs + one spider insert = one complete coupler). Order 1 Pcs for a single axis, 2 Pcs if you need two identical couplers (e.g., X and Y axes), or 5 Pcs for multi-axis machines or to keep spares on hand. Bulk quantities offer a lower per-unit cost.
Yes — flexible jaw couplers are widely used on 3D printer Z-axis assemblies to connect the stepper motor shaft to the lead screw. The spider insert compensates for minor misalignment between the motor and lead screw nut, reducing Z-banding artifacts caused by wobble. Select the OD and bore size that matches your motor shaft and lead screw diameter.
