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When misalignment, vibration, or shaft size mismatch causes your CNC axis to skip steps or your motor to run rough, the root cause is often a rigid or worn coupling. The D30L50 Flexible Plum Coupling is engineered for builders, machinists, and automation enthusiasts who need a reliable, zero-backlash connection between a stepper or servo motor and a lead screw, ball screw, or encoder shaft.
This jaw-style spider coupling features an aluminum alloy body (D30mm outer diameter, L50mm length) with a polyurethane spider insert that absorbs shock and compensates for angular and parallel misalignment. Shaft bore options span 6mm to 19mm (approximately 0.24" to 0.75"), covering both metric and inch shafts (including 6.35mm / 1/4"). Each variant is sold individually (1 Pcs per order).
Typical use cases include DIY CNC router Z-axis and X/Y-axis motor coupling, 3D printer lead screw connections, laser engraver stepper motor drives, and light-duty industrial automation where flexible shaft coupling for stepper motor is required. The spider insert design makes it a direct replacement for rigid couplings in applications demanding vibration damping jaw coupling performance.
| Outer Diameter (D) | 30mm (1.18") |
|---|---|
| Length (L) | 50mm (1.97") |
| Shaft Bore Range | 6mm – 19mm (0.24" – 0.75") |
| Bore Combination | See variant options |
| Body Material | Aluminum Alloy |
| Spider Insert Material | Polyurethane (PU) |
| Coupling Type | Jaw / Plum / Spider |
| Clamping Method | Set Screw |
| Angular Misalignment Tolerance | Typically up to 1° |
| Quantity per Order | 1 Pcs |
| Weight | See variant options |
Measure both shafts you need to connect — the motor output shaft and the lead screw or encoder shaft — using a digital caliper. Select the variant that lists both diameters (e.g., "8mm X 10mm" means one hub bores 8mm and the other bores 10mm). If both shafts are the same size, choose the matching same-size variant such as "8mm X 8mm".
The D30L50 aluminum jaw coupler is suited for light-to-medium duty applications typical of NEMA 17 and NEMA 23 stepper motors used in CNC routers, 3D printers, and laser engravers. For high-torque servo applications or heavy industrial loads, verify the rated torque against your motor's holding torque specification before ordering.
The polyurethane spider insert is a wear component in jaw couplings. Under normal CNC and 3D printer use it lasts for extended periods, but if you notice increased backlash or vibration over time, the insert can typically be replaced independently without replacing the aluminum hubs. Contact us to confirm insert availability for your size.
Yes. The 6.35mm bore variants are specifically included to accommodate 1/4" inch shafts common on North American stepper motors and some encoder shafts. Look for variants listing "6.35mm" on either side of the bore combination (e.g., "6.35mm X 8mm" or "6.35mm X 6.35mm").
The jaw spider design typically compensates for angular misalignment up to approximately 1° and small amounts of parallel (radial) offset. It is not designed for large axial displacement. For best results, align motor and screw shafts as closely as possible during installation — the coupler handles residual misalignment, not gross misalignment.
Set screws can leave minor marks on smooth shafts, which is normal and does not affect function. If your motor shaft has a flat (D-cut), align the set screw to the flat for maximum grip and to minimize shaft marking. Do not overtighten — snug is sufficient for most CNC and 3D printer torque levels.
A rigid coupling transmits torque with zero flex, which means any shaft misalignment creates bearing stress and vibration. This flexible plum jaw coupler uses a polyurethane spider insert between two aluminum hubs to absorb vibration, dampen shock loads, and tolerate small misalignments — making it the preferred choice for CNC stepper motor applications where smooth, quiet motion matters.
