I am running into the issue where it is not traveling far enough. Originally I was using different springs than Marty used, but I found the mcmaster part # in one of the comments on the video and replaced them thinking that would fix the issue. I did this along with sanding the teeth on the pinion thinking that would help. When it hits the 400mm max, it moves just a little bit back, but does not “snap” and retract. It just nudges it basically. It’s almost as if I need to add 5-10 mm to the build area for the homing/ bed leveling process just for the pinion to know to retract or maybe just make the rack on the max side a little bit longer like you said with the bluetac. I was also interested in seeing if there’s a way to manually level the bed as an alternative because I did not see an option to do that.