Frage Installation steps 2.1, 2.1, 5.2 and 6.5

Dears
I'm installing my Stepcraftv2 840 CNC and I have a huge difficulty aligning parts as shown in the attached images from the installation manual (Installation steps 2.1,5.2 and 6.5 asks you to leave 1mm from 2 dimensions and I don't know how to do that)

also what is the impact of a misalignment (the 1mm is not achieved) on the overall accuracy of the machine ?
is there any other way to overcome this issue ?

Best Regards

I had the same problem but I think the most important thing is, that everything has the same distance. I cannot see any problem if all distances are 0.5mm or so.

Yes it is difficult to leave 1mm on each end as shown in the manual. At the end i had to adjust them again and the final stage .