Parametric Compliant Helical Shaft Coupling OpenSCAD 3D print model A highly optimized, fully parametric Compliant Helical Shaft Coupling designed specifically for angular, parallel, and axial shaft misalignments while transmitting rotational torque

This is a highly optimized, fully parametric Compliant Helical Shaft Coupling designed specifically for 3D printing and precision mechanical engineering applications. Using an engineered helical flexure element, this component compensates for angular, parallel, and axial shaft misalignments while maintaining smooth, high-efficiency torque transmission.

Whether you are upgrading a 3D printer Z-axis , building custom CNC machinery , assembling DIY robotics , or engineering a high-torque Sim Racing wheel setup, this customizable beam coupling offers a robust, backlash-free hardware solution.

Key Engineering Features

- Fully Parametric Geometry: Easily customize all critical dimensions including Total Length, Outer Diameter, Bore Diameters, Helix Coils, and Cut Width directly via the OpenSCAD Customizer .

- No-Slip D-Profile Support: Includes a modular drive bore function with adjustable flat depth for secure mounting onto D-shaft motor profiles (e.g., NEMA 17, NEMA 23 stepper motors) to eliminate rotational slipping under load.

- Backlash-Free Torque Transmission: The single-piece spring joint design acts as an efficient beam coupling, removing the "slop" or play common in multi-part jaw or Oldham couplings.

- Stress-Relieved Design: Engineered with structural fillet roots (spherical termination points) at both ends of the helical ribbon to distribute mechanical stress evenly and prevent layer shear under torsional fatigue.

- 3D Print-Optimized (No Supports): Features a built-in mathematical guardrail assert that ensures the helix pitch angle never drops below a self-supporting 45° limit, guaranteeing a flawless, support-less print-in-place execution.

- Clean Engineering Topology: Programmed using precise Overlap Offsets (Epsilon) to eliminate non-manifold coplanar faces, ensuring error-free slicing in PrusaSlicer, Bambu Studio, or Cura. Includes lead-in chamfers on both internal bores for effortless shaft installation.

Applications & Niches

This versatile mechanical component is an ideal replacement or custom solution for:

- 3D Printer Hardware: Fixes Z-wobble when used as a lead screw coupler.

- CNC & Gantry Systems: High-precision rotary-to-linear actuator conversions.

- Sim Racing & RC Cars: Custom driveshafts, steering linkages, and pedal assemblies requiring responsive feedback.

- Automation & Robotics: Flexible joint connections for custom DC motors, servos, and powertrains.

Default Dimensions (As Configured)

Parameter

Default Value

Description

Total Length ($Ltotal$)

80.0 mm

End-to-end coupling length

Outer Diameter ($Dout$)

16.0 mm

External clearance profile

Bottom Drive Bore ($Db1$)

5.0 mm

Equipped with 0.5 mm D-flat depth

Top Driven Bore ($Db2$)

5.0 mm

Standard round bore profile

Helical Cut Width ($Wcut$)

2.0 mm

Thickness of the flexure gap

Helical Turns ($Ncoils$)

0.5 turns

Total rotation of the flexure helix

oftware & Slicing Compatibility

- Source File: Designed and optimized for OpenSCAD 2021.01 or newer. Fully compatible with the built-in Printables Web Customizer.

- High-Definition Rendering: Pre-configured with high-definition rendering ( $$fn = 128$$) for smooth cylindrical geometry while remaining highly efficient (less than 8 GB RAM usage during export).