Elbow Double Joint

thingiverse

A versatile double-revolute joint functions as an elbow joint. It consists of three distinct components: Alpha, Beta, and Charlie. The "Alpha" and "Charlie" parts are designed to slide over the end of a standard 20x20 aluminum extrusion. If you have access to CAD software like Fusion 360, you can modify the .STL files for these parts to fit your specific needs. The 3DP nut and bolt used in this joint were adapted from a design by mike_mattala on Thingiverse (https://www.thingiverse.com/thing:193647). However, these components are relatively weak, particularly when printed with PLA alone. Be cautious not to over-tighten the bolt, as it may snap off at the top. To achieve optimal results, use a 25-30% infill setting at 0.15mm resolution for the main parts of the joint, and finer 0.1mm resolution along with 50% or higher infill for the nut and bolt to ensure a well-defined thread and maximum bolt strength. For my model, I plan to replace the 3DP bolts with high-strength steel ones.