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When shaft misalignment or vibration causes positioning errors in your CNC router, 3D printer, or stepper motor drive system, a rigid coupler becomes the weakest link. The D40 L50mm Flexible Spider Shaft Coupling is engineered for builders and machine operators who need reliable torque transmission without sacrificing flexibility — absorbing angular, parallel, and axial misalignment so your motion system stays accurate under load.
This jaw-type spider coupling consists of two aluminum alloy hubs and a polyurethane spider insert (jaw elastomer). The outer diameter is 40mm (approx. 1.57 in) and the overall length is 50mm (approx. 1.97 in). Bore sizes span 8mm to 22mm (approx. 0.31–0.87 in), with both same-bore and cross-bore configurations available across 120+ variants to match your exact shaft pairing.
Typical use cases include CNC stepper motor shaft coupling for lead screw drives, servo motor coupling in laser engravers and plasma tables, and flexible shaft connector applications in DIY automation rigs where vibration damping and zero-backlash performance are critical to part accuracy.
Two-piece aluminum hub with polyurethane spider insert transmits torque while absorbing shock loads — reducing wear on motor bearings and linear guides.
Wide Bore Range: 8mm–22mmOver 120 shaft diameter combinations available, including same-bore (e.g., 8×8mm) and cross-bore (e.g., 8×12mm) pairings for mixed-shaft motor-to-leadscrew connections.
Misalignment CompensationAccommodates angular misalignment (typically up to 1°), parallel offset, and axial displacement — protecting your drive train from binding caused by imperfect shaft alignment.
Vibration Damping Spider InsertThe polyurethane elastomer spider insert absorbs vibration and reduces noise during high-speed stepper motor operation, contributing to smoother motion and quieter machine cycles.
Lightweight Aluminum Alloy HubsMachined aluminum alloy construction keeps rotational inertia low — important for responsive acceleration and deceleration in CNC and 3D printing applications.
Set Screw ClampingEach hub is secured to the shaft via set screws, allowing tool-free disassembly and reassembly for maintenance, motor swaps, or lead screw replacements.
| Coupling Type | Jaw / Spider (Oldham-style elastomer) |
|---|---|
| Outer Diameter (D) | 40mm (1.57 in) |
| Overall Length (L) | 50mm (1.97 in) |
| Bore Range | 8mm – 22mm (0.31 – 0.87 in) |
| Hub Material | Aluminum alloy |
| Spider Insert Material | Polyurethane (PU) elastomer |
| Shaft Fixation | Set screw |
| Misalignment Tolerance | See variant options |
| Max Torque | See variant options |
| Finish | Natural anodized / machined aluminum |
| Quantity per Order | 1 Pcs |
Measure both shafts you need to connect — your motor shaft and your lead screw or driven shaft. Select the variant that matches both diameters (e.g., 8mm × 12mm means one hub bores 8mm and the other bores 12mm). If both shafts are the same size, choose a same-bore variant like 10mm × 10mm.
The spider jaw design compensates for angular misalignment (slight angle between shaft centerlines), parallel offset (shafts running side by side but not collinear), and axial displacement (shafts moving toward or away from each other). For best results, minimize misalignment during installation — the coupling absorbs residual error, not gross misalignment.
Spider jaw couplings with a polyurethane insert offer near-zero backlash under normal CNC and stepper motor loads. The elastomer spider fills the gap between the jaw teeth, transmitting torque with minimal play. For ultra-precision applications requiring absolute zero backlash, consider a rigid beam coupling instead.
Yes. NEMA 17 motors typically have a 5mm shaft, but many upgraded versions use 8mm shafts. NEMA 23 motors commonly use 6.35mm (1/4 in) or 8mm shafts. Select the bore variant that matches your specific motor shaft diameter. The 40mm outer diameter fits within standard motor mount clearances for both NEMA 17 and NEMA 23 frames.
The polyurethane spider insert is a separate component between the two aluminum hubs. In many jaw coupling systems, the insert can be replaced without replacing the hubs. Check that the spider geometry matches before ordering a replacement insert, as jaw tooth profiles vary by manufacturer.
This D40 L50mm coupling is designed for low-to-medium speed CNC and stepper motor applications. For high-speed spindle or servo applications exceeding several thousand RPM, verify the maximum RPM rating with the specific variant. The aluminum hubs and PU spider are well-suited for the speed ranges typical of CNC routers, laser engravers, and 3D printer axis drives.
Slide each hub onto its respective shaft, aligning the set screw hole with a flat on the shaft if present. Insert the polyurethane spider between the two hubs, meshing the jaw teeth. Tighten the set screws with an appropriate hex key to the recommended torque for your shaft diameter. Ensure both hubs are flush and the spider is fully seated before running the motor.
