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When shaft misalignment, vibration, or backlash causes your CNC machine or stepper motor drive to lose precision, the weak link is almost always the rigid coupling. Engineers, machine builders, and DIY CNC enthusiasts who demand repeatable accuracy need a coupling that absorbs angular and parallel misalignment without transmitting shock loads to bearings or encoders.
These flexible plum spider jaw shaft couplers consist of two aluminum alloy hubs and a polyurethane (PU) spider insert. Available outer diameter × length combinations of 25 × 30 mm (~0.98" × 1.18") and 40 × 55 mm (~1.57" × 2.17"), with bore sizes ranging from 6 mm to 20 mm (approximately 0.24" to 0.79"). Sold individually (1 PCS) or in value packs of 2 or 5 pieces.
Ideal for CNC router Z-axis lead screw connections, 3D printer stepper motor couplings, laser engraver drive shafts, and general-purpose flexible shaft coupling for stepper motor applications where vibration damping and zero-backlash torque transmission are critical.
The polyurethane (PU) spider element absorbs torsional shock and running vibration, protecting motor bearings and encoders from fatigue damage during continuous CNC operation.
Accommodates angular misalignment (typically up to 1°) and parallel offset between motor and lead screw shafts, reducing stress on motor shaft bearings and extending service life.
Lightweight yet rigid aluminum alloy hub bodies deliver low rotational inertia for fast acceleration and deceleration cycles — essential for high-speed CNC and 3D printer stepper motor applications.
Split-clamp hub design grips the shaft firmly with set screws, eliminating slip under load and ensuring consistent torque transmission without shaft damage.
Available in 1, 2, or 5-piece quantities — stock up for multi-axis CNC builds or keep spares on hand for rapid maintenance without downtime.
Bore options from 6 mm to 20 mm cover the most common stepper motor shaft diameters and lead screw end dimensions, making these couplers a versatile fit across CNC router, laser, and 3D printer platforms.
| Product Type | Flexible Plum Spider Jaw Shaft Coupler |
|---|---|
| Hub Material | Aluminum Alloy |
| Spider Insert Material | Polyurethane (PU) |
| Outer Diameter × Length | 25 × 30 mm / 40 × 55 mm (see variant options) |
| Bore Size | 6 mm, 6.35 mm, 17 mm, 19 mm, 20 mm (see variant options) |
| Fixing Method | Clamp-style with set screws |
| Rated Torque | See variant options |
| Max Speed | See variant options |
| Angular Misalignment Tolerance | Typically up to 1° |
| Finish | Natural anodized aluminum |
| Quantity per Pack | 1 PCS / 2 PCS / 5 PCS (see variant options) |
| Application | CNC routers, 3D printers, laser engravers, stepper/servo motor drives |
Match the bore size to your motor shaft diameter and lead screw end diameter. Common NEMA 17 motors use a 5 mm shaft, but many CNC lead screws have 6 mm or 6.35 mm (1/4") ends. NEMA 23 motors typically use 6.35 mm or 8 mm shafts. Check both the motor shaft and the lead screw end before selecting your bore combination from the variant options above.
The 25 × 30 mm coupler (OD × Length) is suited for smaller bore shafts (6–6.35 mm) and compact motor mounts such as NEMA 17 setups. The 40 × 55 mm coupler handles larger bore shafts (17–20 mm) and is designed for heavier-duty NEMA 23/34 stepper or servo motor applications with higher torque requirements.
Yes. The polyurethane spider insert allows the coupling to flex and accommodate angular misalignment (typically up to approximately 1°) and minor parallel offset between the motor shaft and lead screw. This flexibility reduces bearing load and extends the life of both the motor and the driven component. It is not designed for large misalignment — always align shafts as closely as possible during installation.
Yes. The jaw coupling design allows the polyurethane spider element to be replaced independently of the aluminum hubs. If you notice increased vibration or backlash over time, inspect the spider insert first — replacing it restores coupling performance without replacing the entire assembly.
The aluminum alloy hubs have natural corrosion resistance suitable for typical indoor workshop environments. For humid or mildly corrosive conditions, the anodized surface provides additional protection. The PU spider insert is resistant to oils and mild chemicals. For highly corrosive or submerged environments, contact us to confirm suitability.
Multi-axis CNC machines (X, Y, Z axes) each require a separate coupler. Purchasing a 2 or 5-pack reduces per-unit cost and ensures you have matched spares on hand for fast maintenance. For 3-axis CNC routers, the 5-pack is a practical all-in-one solution covering all axes plus two spares.
Yes. These flexible jaw couplers are compatible with both lead screws and ball screws, provided the screw end diameter matches the selected bore size. They are also suitable for connecting stepper or servo motor shafts to encoder shafts, pump shafts, and other rotating machinery within the rated torque range.
