Two things wrong there. Firstly: making your own CNC couples without a set of taps for making the clamping work, or a drill press for drilling out the holes without masses of error, or some aluminium in the right shape so I don't have to break something, is very very very hard. Secondly, I do have something that resembles rubber tubing. I have quite a bit of heat-shrink tubing that is overwise sitting there staring at me saying "hey, over here. I want to hug your shaft!"
So, tonight, I'm going to drill out proper bolt holes in the beds to lock the polymorph in place, and then I'm going to shrink on the steppers to the studding. That means, apart from software, I'm almost ready for a full XY demo. :)