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When shaft misalignment causes vibration, noise, or premature bearing wear in your CNC router, 3D printer, or automation rig, the coupling is almost always the culprit. Engineers and DIY builders who demand tight motion control need a coupler that absorbs angular and parallel offset without sacrificing torque transmission. These aluminum plum (jaw) shaft couplers are machined to close tolerances, making them a reliable drop-in upgrade for servo motor, stepper motor, and lead-screw drive systems.
Each coupler is CNC-machined from aluminum alloy and features a spider/plum elastomer insert seated between two aluminum hubs. Outer diameters span Ø14 mm (0.55 in) to Ø80 mm (3.15 in); body lengths range from 22 mm (0.87 in) to 114 mm (4.49 in); and bore diameters (d1/d2) cover 3 mm up to 45 mm, accommodating a wide range of motor and lead-screw shaft combinations. Both shaft bores are clamped via set-screw, and the bore sizes for each variant are listed in the variant selector — specify d1 and d2 in the order remarks field.
Typical use cases include CNC router Z-axis lead-screw coupling, servo motor shaft coupling for pick-and-place automation, stepper motor flexible coupling for 3D printer drive systems, and general-purpose flexible shaft coupling for industrial conveyor or rotary table builds. Long-tail search terms: flexible jaw coupling all bore sizes, plum coupler servo motor CNC, aluminum spider coupling stepper motor.
| Material | Aluminum alloy (CNC-machined hubs) + polyurethane spider insert |
|---|---|
| Outer Diameter (OD) | Ø14 mm / Ø20 mm / Ø25 mm / Ø30 mm / Ø35 mm / Ø40 mm / Ø45 mm / Ø55 mm / Ø65 mm / Ø80 mm |
| Body Length | 22 mm – 114 mm (see variant options) |
| Bore Diameter (d1 / d2) | 3 mm – 45 mm (range varies by OD; see variant options) |
| Shaft Fixing Method | Set screw (hex socket) |
| Coupling Type | Flexible jaw / plum (spider) coupling |
| Finish | See variant options |
| Quantity per Order | 1 pc (as listed per variant) |
| Angular Misalignment Tolerance | Typically up to 1° (varies by size and load) |
| Parallel Offset Tolerance | See variant options |
Match the outer diameter (OD) to the torque and shaft size of your motor. As a general rule, larger OD couplers handle higher torque. For length, choose a body length that provides enough clamping depth for both shafts — typically each shaft should insert at least 10–15 mm into its hub. Check your motor datasheet for shaft diameter, then select the variant whose bore range (d1/d2) includes that value.
d1 is the bore diameter of the motor-side hub and d2 is the bore diameter of the load-side hub (e.g., lead screw or output shaft). Each variant lists the allowable range (e.g., 4–10 mm). After selecting your variant, enter your required d1 and d2 values in the order remarks field at checkout. The coupler will be prepared to those bore sizes.
Yes. The polyurethane spider insert between the two aluminum hubs accommodates angular misalignment (typically up to 1°) and small amounts of parallel offset. This makes it suitable for applications where perfect shaft alignment is difficult to achieve, such as DIY CNC builds or retrofitted motor mounts. For severe misalignment, consider realigning the shafts mechanically first.
The aluminum hubs offer natural oxidation resistance suitable for indoor workshop and light industrial environments. For prolonged exposure to moisture, salt spray, or chemicals, consider applying a protective coating or selecting a stainless-steel alternative. The polyurethane spider insert is resistant to oils and mild solvents.
NEMA 17 motors typically have a 5 mm shaft, and NEMA 23 motors commonly use 6.35 mm or 8 mm shafts. Select a variant whose d1/d2 bore range includes your motor shaft diameter. For example, the Ø20 mm OD variant with a 4–10 mm bore range covers both NEMA 17 (5 mm) and NEMA 23 (6.35 mm / 8 mm) shafts.
Rated torque and maximum RPM vary by outer diameter and body length. Larger OD variants handle higher torque loads. For specific torque ratings for your chosen size, please contact us to confirm — we can provide technical data for the exact variant you select.
Yes, this is one of the most common applications. Select a variant whose bore range covers both your motor shaft diameter and your lead screw diameter (typically 8 mm, 10 mm, or 12 mm for T8/T10/T12 lead screws). Specify d1 (motor shaft) and d2 (lead screw) in the order remarks. The flexible insert helps dampen vibration and reduce Z-banding artifacts in 3D printers.
