Okay had some time and printed all the cubes out and this was my results:
I put down an rough average based off three or more measurements on each side. It looks like I really don’t see a difference in Y compared to X till I get to the 60x60mm cube. Z looks to be just about right no matter what size I print at but X and Y look to be off by .2mm or more on all the prints tested.
I also changed out my $10 Harbor Freight Pittsburgh digital caliper for a slightly more upscale $25 one made by iGaging to see if I can get more consistent measurements. I then tightened the belts for both X and Y so that I think helped get both axis a little more consistent.
Not sure what to do here, when I print benchies and other prints that test other aspects of the printer I get great results outside of dimensional accuracy. I know .2mm tolerance is fine for most prints but if I wanted to print single prints that involve interconnected moving parts like the NASA wrench I would assume I would what to try dial the accuracy in a little more right or am I just driving myself crazy?
Any other things I could try/test to see if I can get my X/Y closer to the accuracy of my Z axis?