I picked up a 7×7 mill from Zen toolworks a while ago. I did the basic assembly and powered it up with an old 24v power supply. It moved, but locked up on the far X axis, and the far Y axis, and stalled with any high speed movement. At that point it all got boxed up for a house move, and stayed that way for a year. I’ve recently dragged it back out and thrown some more time at getting it setup.
I lined up the bottom frame using a machinist square. It was close enough that I could just shim out one corner with a piece of paper. The stepper motors pull more power the faster they run. The old 2.5 amp 24V psu wasn’t providing enough power as the acceleration kicked in. I’ve swapped it out for new 14.6 amp 24v psu. I still found some issues with the alignment of the anti-backlash nut on the Y axis. The problem with this is that you can’t easily access the anti-backlash nut. After a good look around the machine, and I decided to remove the 16 screws securing the back plate from the gantry. I could then access the mounting screws for the anti-backlash nut by loosening the mounting screws and moving it to the far side of the Y axis. I could then tighten the mounting screws with the anti-backlash nut in the correct alignment.
Also, I got a video cam for my birthday, so here’s a time lapse of the job progress.