Customizable "Okkake Daisen Tsugi" joint

thingiverse

Designed for joining thin square bars firmly to construct arbitrarily long bars and trusses that can be disassembled, modified and repaired easily. Originates from traditional Japanese wood joinery called "Okkake Daisen Tsugi" (Rabbed Oblique Scarf Joint) scaled down to 1/20 of the original dimension. Works from 4mm square bars. Supposed to be used as an OpenSCAD module for various applications. 4.8mm (the picture above) is totally usable, with >100N tensile strength (PETG and PLA), but not to be used for safety-critical applications because of the variations in strength. If tensile/bending load is small and static, plugs could be omitted by setting "plug" to 0. First of all, test and customize gaps and the plug size. Increasing/decreasing gaps by 0.02mm can make big difference. Note that the center z-shaped hook is vertically slanted to ensure tight contact. Application to extensible trusses can be downloaded from https://www.thingiverse.com/thing:5394703, and extensible space frames can be downloaded from https://www.thingiverse.com/thing:5397974. Further details can be found in https://doi.org/10.31224/2338 . (May 24, 2022) added a switch to turn off test printing for use from other .scad files.