This is just a plug to cap some tubing. I wanted to keep dust, chips, spiders and other crap from accumulating in the MPCNC router rails. It fits my MPCNC router US 3/4in EMT in my case. However it can be scaled in most slicers to fit other sizes. I use Simplifi3D and that will allow you to scale the object in X and Y before printing. Leave Z alone unless you want to change the thickness of the cap. I’ve included one with a hole for stuffing wires thru.
I tend to print at 0.1mm layer thickness but I'm retired and not in a hurry. Besides it looks much better than printing a pile of ropes. Just my opinion.