Parametric dowel and tube joiners

Parametric connector generator for round dowels, tubes, rods, and light pipe projects

This single OpenSCAD file creates configurable 2-way, 3-way, 4-way, 5-way, or 6-way joiners with adjustable diameters, lengths, angles, and reinforcement options. It is designed for practical structural prototyping: furniture mockups, workshop jigs, temporary enclosures, display frames, greenhouse-like builds, and lightweight utility structures.

OpenSCAD is free and available at https://openscad.org

What This File Does

• Generates round-socket connectors from one configurable script.
• Supports connector modes from straight couplers up to 6 connectors.
• Lets you set a global arm length or individual lengths per connector.
• Lets you tune branch geometry with per-connector vertical and horizontal angles.
• Optional heat-insert/bolt retention features for added clamping/security.
• Optional internal grip ridges for more friction on inserted dowels/tubes.
• Offers two structural styles:
  • Solid: fuller shell, straightforward strength.
  • Scaffold: lighter body with I-beam style bracing and rounded elbow fill.
• Includes a print-tolerance setting.

Instructions

1. Match diameter to your real stock:
   1. Set Dowel_diameter to the nominal rod/tube size.
   2. Use Print_tolerance to tune fit (increase if too tight).
2. Choose connector topology first:
   1. Connector_count = 2..6 depending on how many joins you need.
3. Set geometry second:
   1. Adjust Connector_2_angle for the main top/bottom coupler.
   2. Set additional connector angles and lengths with Connector_3/4/5/6_* controls as needed.
4. Pick strength-to-weight behavior:
   1. Use solid for maximum material around intersections (heat inserts may not work with this mode).
   2. Use scaffold for lighter parts with strategic I-beam support.
5. Improve holding force when needed:
   1. Enable Use_grip_ridges for friction fit.
   2. Enable Use_heat_insert for mechanical retention with hardware.

Printing Notes

These will be very dependent on what you're using these joiners for, but here's a baseline I typically start from:

• Material:
  • PLA for quick fit checks and indoor prototypes.
  • PETG/ABS/ASA for warmer or higher-stress use.
• Perimeters:
  • 4-6 walls for structural connectors, or pick Bambu's Strength profile.
• Infill:
  • 20-35% for general use; increase for load-bearing builds.
• Layer height:
  • I generally go with 0.2mm.
• Fit tuning:
  • If insertion is too tight, increase `Print_tolerance` in small steps.
• Support and Bed Adhesion
  • Tree, on build plate only
  • Brim: Auto