Printing nozzle polishing adaptor for proxxon rotary tool

This adaptor allows you to mount a Creality Ender 3 standard nozzle directly on the shaft of a proxxon micromot rotary tool (M8x0.75 thread), and reshape the noozle with fine sandpaper. I attached photos of what I did with my 0.4 nozzle (before / after). The scratches left by the brass brush that I was using to clean it are clearly visible on the "before" picture. A nozle with a large or irregular flat tip can cause bridging issues as the material tend to stick to the noozle, this was the motivation for this design.

My first attempt used a inner thread on the nozzle side, but I obtain a much better centering with the hexagonal fit. I slightly sanded the faces before on a flat surface, to remove excessive irregularity. The nozzle hole was centered quite accurately in may case, but I cannot guarantee that it will be as good with any nozzle or printing.

As a tight fit is required to maintain the nozzle firmly (and the adaptor on the shaft), dimensions may need adjustment depending on the printer, settings, and materials (easy to do in the OpenScad file). You will need this thread library to compile it.