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When a misaligned or rigid shaft connection causes vibration, noise, or premature wear in your CNC machine or automation system, the root cause is almost always the coupling. Engineers and DIY builders working with stepper motors, servo drives, and lead screws need a flexible jaw coupling that absorbs shock, compensates for minor misalignment, and transmits torque without backlash. This flexible plum spider jaw shaft coupler is designed for exactly that application.
Each coupling consists of two precision-machined aluminum hubs and a polyurethane spider insert (plum-type elastomer). Available in 3-jaw (Ø45mm OD) and 4-jaw (Ø55mm and Ø65mm OD) configurations, with overall lengths ranging from 55mm to 110mm (~2.2" to 4.3") and bore diameters from 8mm to 38mm (~0.31" to 1.50"). Both equal-bore (d1=d2) and unequal-bore (d1≠d2, leave a message) options are offered.
Typical use cases include CNC router Z-axis lead screw connections, 3D printer motor-to-rod couplings, laser engraver drive shafts, and general industrial automation shaft-to-shaft connections where angular and parallel misalignment compensation is required.
Choose 3-jaw (Ø45mm) for lighter-duty CNC and 3D printer applications, or 4-jaw (Ø55mm / Ø65mm) for higher-torque servo and industrial drive systems.
The polyurethane spider insert absorbs angular, parallel, and axial misalignment, reducing vibration transmission to connected components and extending bearing life.
Tight hub-to-spider fit ensures responsive, backlash-free motion — critical for CNC positioning accuracy and closed-loop servo control.
Bore sizes from 8mm to 38mm (equal or unequal) cover the vast majority of stepper motor shaft and lead screw diameter combinations used in CNC and automation builds.
Lightweight yet rigid aluminum hubs resist corrosion and maintain dimensional stability across typical workshop temperature ranges, keeping coupling geometry consistent over time.
Need d1≠d2? Select the "Leave a message" bore option and specify your exact shaft diameters at checkout — machined to your dimensions.
| Product Type | Flexible Plum Spider Jaw Coupling |
|---|---|
| Hub Material | Aluminum Alloy |
| Spider Insert Material | Polyurethane (PU) Elastomer |
| Jaw Configuration | 3-jaw (Ø45mm OD) / 4-jaw (Ø55mm, Ø65mm OD) |
| Outer Diameter (OD) | 45mm / 55mm / 65mm (~1.77" / 2.17" / 2.56") |
| Overall Length (L) | 55mm – 110mm (~2.17" – 4.33") — see variant options |
| Bore Diameter Range | 8mm – 38mm (~0.31" – 1.50") |
| Equal Bore (d1=d2) | 8mm×8mm up to 38mm×38mm |
| Unequal Bore (d1≠d2) | Available — specify at checkout |
| Finish | See variant options |
| Quantity per Order | 1 Piece |
| Applicable Motors | Stepper motors, servo motors, CNC drives |
The 3-jaw version (Ø45mm OD) is suited for lighter-duty applications such as NEMA 17 stepper motors, 3D printers, and small CNC routers where torque requirements are moderate. The 4-jaw versions (Ø55mm and Ø65mm OD) handle higher torque loads and are recommended for NEMA 23/34 steppers, servo motors, and industrial automation drives. If you are unsure, match the OD to your motor flange size and check the bore range covers your shaft diameter.
Measure your motor shaft diameter (d1) and your lead screw or driven shaft diameter (d2) with a caliper. Select the variant where both d1 and d2 match your measurements. If d1 equals d2, choose the corresponding equal-bore option (e.g., 10mm×10mm). If your two shafts differ in diameter, select "d1≠d2, Leave a message" and specify both dimensions in your order notes.
The polyurethane spider insert provides compensation for angular misalignment (typically up to 1°), parallel offset (typically up to 0.2–0.5mm), and minor axial displacement. These are conservative operating values — exceeding them will accelerate spider wear. For best results, align shafts as closely as possible during installation and use the coupling's flexibility as a buffer, not a primary alignment correction.
Yes. The polyurethane spider (plum insert) sits between the two aluminum hubs and can be removed and replaced without disassembling the entire drive system. This makes maintenance straightforward — if you notice increased vibration or visible spider wear, simply slide the hubs apart, swap the insert, and reassemble. Contact us to confirm spider insert availability for your specific OD size.
Yes, provided the bore diameter matches your motor shaft and lead screw. The 3-jaw Ø45mm variant is widely used on NEMA 17 (5mm shaft) and NEMA 23 (6.35mm or 8mm shaft) CNC and 3D printer builds. Confirm the bore range listed in the variant covers your shaft sizes. The coupling is compatible with T8, T12, and similar lead screw diameters commonly used in desktop CNC and FDM 3D printers.
The hubs are machined from aluminum alloy, which offers a good strength-to-weight ratio and natural corrosion resistance suitable for indoor workshop and light industrial environments. The spider insert is polyurethane, which is resistant to oils, greases, and moderate chemical exposure. For outdoor or high-humidity environments, consider applying a light protective coating to the aluminum hubs.
Yes. Select the "d1≠d2, Leave a message" variant and include both shaft diameters in your order message (e.g., "d1=8mm, d2=10mm"). The coupling will be machined to your specified dimensions. Please double-check your measurements before ordering, as custom-bored couplings cannot be re-bored after machining.
