I did not use limit switches (not yet anyway). I hope to get some time to make a cut today. I've done a little sharpie marker test and everything seems to be close. As I was building my table I constantly checked to make sure everything was squared, and that made it easier at the end. When I mounted the gantry it just about aligned itself. I played with it some to check it out, and it would not move if I purposely moved the gantry out of align. I mounted my carriages on first with all the bearings, and then mounted the gantry on to the carriages. I also checked my X distance, but honestly it seemed to align itself, because my setup would bind up if it were not aligned.