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When a rigid coupling transmits every vibration and micro-misalignment directly into your motor bearings, precision suffers and components wear prematurely. Engineers and CNC builders who demand smooth, low-backlash power transmission rely on flexible jaw couplings to absorb angular, parallel, and axial misalignment without sacrificing torque capacity. This flexible plum spider jaw coupling is designed for stepper motors, servo drives, lead screws, and general shaft-to-shaft connections in CNC routers, 3D printers, laser engravers, and light industrial machinery.
Each coupling consists of two aluminum alloy hubs and a polyurethane spider insert (plum-type elastomer). Outer diameters span 35 mm to 45 mm (approximately 1.38 in to 1.77 in), with lengths from 40 mm to 85 mm (approximately 1.57 in to 3.35 in). Bore sizes range from 6 mm to 25 mm depending on the selected variant, accommodating a wide range of motor shaft and lead-screw diameters. Available in 1-piece or 5-piece packs.
Typical applications include CNC shaft coupler replacements on router Z-axis assemblies, stepper motor jaw coupling upgrades on delta 3D printers, and flexible spider coupling installations on small milling machines where vibration damping and misalignment compensation are critical to surface finish quality.
3-Jaw Spider Design
The polyurethane plum spider insert sits between three-jaw aluminum hubs, providing torsional flexibility and vibration damping while maintaining accurate angular positioning.
Wide Size Range
OD options from 35 mm to 45 mm and lengths from 40 mm to 85 mm cover the most common CNC and motion-control shaft sizes in a single product listing.
Misalignment Compensation
Accommodates angular misalignment (typically up to 1°), parallel offset, and axial displacement, reducing bearing load and extending drivetrain service life.
Low Backlash Transmission
The interference-fit spider insert minimizes rotational play, making these couplings suitable for closed-loop servo systems and precision lead-screw drives.
Set-Screw Clamping
Each hub is secured to the shaft via set screws, allowing tool-free bore adjustment and quick shaft swaps during machine reconfiguration.
Single or 5-Pack Options
Order one coupling for a single-axis repair or choose the 5-piece pack for multi-axis builds and workshop stock — both options ship in the same variant matrix.
| Coupling Type | Flexible Plum Spider Jaw (3-jaw) |
|---|---|
| Outer Diameter (D) | 35 mm / 40 mm / 45 mm (see variant options) |
| Length (L) | 40 mm – 85 mm (see variant options) |
| Bore Diameter (d1 × d2) | 6 mm – 25 mm (see variant options) |
| Inner Bore Range | 6 mm to 25 mm depending on OD selected |
| Hub Material | Aluminum alloy |
| Spider Insert Material | Polyurethane elastomer |
| Shaft Fixing Method | Set screw clamping |
| Misalignment Tolerance | Angular: typically ≤1°; Parallel: see variant options |
| Pack Quantity | 1 Pcs or 5 Pcs (see variant options) |
| Weight | See variant options |
First measure your motor shaft diameter (d1) and the mating shaft or lead-screw diameter (d2). Then select the OD/Length combination that fits your motor frame — NEMA 17 motors typically pair with D 35–40 mm couplings, while NEMA 23 motors often use D 40–45 mm. If d1 ≠ d2, choose the "d1≠d2, Leave a message" option and specify both diameters in your order notes.
Yes. The polyurethane spider insert allows angular misalignment of typically up to 1° and absorbs minor parallel offset. For best results, align shafts as closely as possible during installation — the coupling compensates for residual misalignment, not gross assembly errors.
The polyurethane spider (plum insert) is a separate component seated between the two aluminum hubs. In most jaw coupling designs the insert can be replaced independently without replacing the hubs. Contact us to confirm insert availability for your specific size.
The aluminum alloy hubs offer good corrosion resistance for typical indoor workshop conditions. The polyurethane spider insert is inherently moisture-resistant. For outdoor or high-humidity environments, periodic inspection is recommended. Avoid prolonged exposure to strong acids or solvents.
Both options contain identical couplings. The 1-piece pack is ideal for single-axis repairs or prototype builds. The 5-piece pack offers a lower per-unit cost and is suited for multi-axis CNC machines, batch production, or workshop inventory. Select your preferred quantity in the "Bore (d1×d2) & Amount (Pcs)" option above.
Slide each hub onto its respective shaft until the shaft end is flush with or slightly recessed from the outer face of the hub. Insert the polyurethane spider between the two hubs, then tighten the set screws with an appropriate hex key. Ensure both set screws are torqued evenly to prevent shaft slippage under load.
Yes. The interference-fit spider insert minimizes rotational backlash, making these jaw couplings compatible with encoder-equipped servo drives where positional accuracy is critical. For ultra-high-precision applications requiring near-zero backlash, verify the specific bore-to-hub fit tolerance for your selected variant.
