Just confirming that when I put this together it was just like Ryan said… assemble, and put in the rails, and it’s square.
I have the 23.5mm kit for 3/4 EMT conduit. In building the center piece, the bolts fit in smoothly and the bearings generally just touched the conduit when I slid it in. At that point, I checked it with a 30cm square that I have and found that it’s perfect within my ability to measure (sub 1/2mm over 30cm). I placed the square on one of the pipes and then looked at where it sat on the other pipe to see that it was indeed square. I think this is what you are doing, but it’s hard to tell in the picture. I might set it up so you can see the square touch one pipe and not the other all in the same picture. like this:https://www.vicious1.com/wp-content/uploads/2015/07/IMG_20160527_13131101.jpg
For the first few runs on the machine, it was a bit rough because there was the coating on the conduit. After a few runs though, the coating started to flake off and wear down and the movement settled right in and became very smooth.
It MIGHT be worth taking the whole center piece apart again and then reassembling it methodically just to see if you can figure out what’s wrong with it. In my case, everything fit together very nicely and with appropriate tightness without changing any of the holes.
My machine is 2’x2′ and it really doesn’t need the steps that Ryan takes to square his up each time. it’s so close when I’ve checked, that I don’t do anything to it. and again, it just came together like this, no real work at all to square it.
Good luck… it’s got to be very frustrating.