K8200 Z axis rework V2

thingiverse

This is a further refinement of my cable driven Z axis for the K8200 or 3Drag. It uses a cable loop to ensure the Z axis is driven from both ends, and at the same time provides a large degree of "z wobble" isolation, though a severely bent leadscrew will still show up in the print as artefacts in layer height due to small changes in cable tension. The cable I am using is a 3mm thick steel core clothesline, possibly overkill for the task, but works well for me. The mod is complicated, and has many parts. I have added instructions in the SCAD file and suggestions for the order of assembly, but still have to make a proper catalogue of all the hardware used (for example the lengths of M5 bolts used to attach each part to the printer frame. The printed threads make use of the threads.scad library from Dan Kirshner (https://dkprojects.net/openscad-threads/threads.scad) which is GPL3 licensed, hence the change of license from the earlier version. If this dependence is removed the rest of the code can be distributed under a CC-BY-SA licence like it was on the old one. The threads take forever to render, which is why I have included the STL files for the threaded parts. I have not included the rest of the STL files because I expect anyone attempting to build this to check the notes in the code and tweak things to suit their hardware and leadscrew variant.