OK the problem I was chasing was getting all of my z-axis bearings engaged. I can’t get the inside bearings to make contact with the pipes Lets call it less than a mm but bigger than .5.the outside bearings are clamped hard just to get there.
Part of me is thinking hard about a reprint, I did do further tuning to my printer after i printed the core and maybe there was enought error to wreack the tollerances. During the time I was doing the printing I ran into the tool “califlower” my x axis was out iirc 104 steps/mm corrected to 98.5 that is 6% or so probaly not trivial. I might just start the reprint with the z motor mount and its partner.
The problem I cause is that the x-axis now makes a sound like the belt is slipping and the axis goes out of square. My assumption is that I probably induce some binding. y-axis does not exhibit the problem.