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When misalignment between a servo motor and a lead screw causes vibration, lost steps, or premature bearing wear, the coupling is often the first component to blame. Engineers and machine builders working on CNC routers, 3D printers, laser engravers, and precision automation equipment need a coupling that transmits torque faithfully while absorbing angular and axial misalignment without introducing backlash. This D56 double diaphragm shaft coupling is designed for exactly that application.
The coupling body is machined from aluminium alloy and features a double diaphragm disc design that provides flexible torque transmission. The outer diameter is 56 mm (2.20 in) and the overall length is 63 mm (2.48 in). Bore sizes for both shaft ends (d1 and d2) are selectable from 10 mm to 28 mm (0.39 in to 1.10 in), with clamping achieved via split-clamp collar and set screws. The diaphragm elements are typically stainless steel, providing corrosion resistance in workshop environments.
Typical use cases include servo-to-ballscrew connections on CNC milling machines, stepper motor shaft couplings on desktop routers, and encoder shaft couplings on rotary indexing tables — all applications where a zero-backlash double diaphragm CNC coupler is required to maintain positional accuracy.
| Coupling Type | Double Diaphragm Disc |
|---|---|
| Body Material | Aluminium Alloy |
| Diaphragm Material | Stainless Steel |
| Outer Diameter (OD) | 56 mm (2.20 in) |
| Overall Length (L) | 63 mm (2.48 in) |
| Bore d1 Range | 10–28 mm (0.39–1.10 in) |
| Bore d2 Range | 10–28 mm (0.39–1.10 in) |
| Bore Tolerance | See variant options |
| Max. Torque | See variant options |
| Max. Speed | See variant options |
| Shaft Fixing Method | Split-Clamp Collar + Set Screws |
| Backlash | Zero (diaphragm design) |
| Finish | Natural Anodised / Mill Finish |
| Quantity per Order | 1 pc |
Measure the diameter of each shaft you need to connect — your motor shaft (d1) and your lead screw or driven shaft (d2). Select the variant that matches both diameters. If your shafts are the same size, choose a same-bore variant (e.g., d10–d10). If they differ, choose the appropriate mixed-bore variant (e.g., d10–d14). Bore sizes range from 10 mm to 28 mm on both ends.
A double diaphragm coupling uses two thin flexible disc elements (diaphragms) to transmit torque while accommodating angular, axial, and parallel misalignment between shafts. Unlike jaw or oldham couplings, the diaphragm design achieves zero backlash — meaning there is no rotational play between input and output shafts. This is critical for CNC and servo applications where positional accuracy depends on every motor step being faithfully transmitted to the driven axis.
Yes. The D56 double diaphragm coupling is compatible with both stepper motors and servo motors, provided the shaft diameter falls within the 10–28 mm bore range. It is also suitable for connecting encoder shafts, ballscrews, and lead screws in precision motion systems.
The aluminium alloy body offers good natural corrosion resistance and is typically anodised or mill-finished for additional protection. The diaphragm elements are stainless steel, which resists rust in humid workshop environments. This coupling is suitable for indoor CNC and automation use. For harsh chemical or outdoor environments, contact us to confirm suitability.
Yes. The double diaphragm design accommodates angular misalignment (typically up to 1°), axial misalignment, and small amounts of parallel offset. However, excessive misalignment will reduce coupling life and may introduce vibration. For best results, align shafts as accurately as possible during installation and use the coupling's flexibility only to absorb residual misalignment.
The coupling uses a split-clamp collar design with set screws. Slide each end of the coupling onto the respective shaft, align the coupling centrally between the two shaft ends, then tighten the clamping screws to the recommended torque using an appropriate hex key. Ensure both shafts are clean and free of oil before installation to maximise clamping force. No special tools or press-fit equipment are required.
Confirm the following before ordering: (1) both shaft diameters fall within the 10–28 mm range and match the selected variant; (2) the 56 mm OD and 63 mm length fit within your machine's available space; (3) the torque and speed requirements of your application are within the coupling's rated capacity — refer to the variant specifications or contact us to confirm. Selecting the correct bore combination is the most important step.
