welding steel base or just getting aluminium extrusion

[Neale]

Was just a thought after watching that video, i know i will be needing straight edges and engineer squares but most of these videos on youtube are just some guy pointing his camera at an engineer square and going up and down which lasts 20 seconds long lol. i am still reading on here and watching other people tips and tricks but all i can picture in my head is getting one rail on and have it as straight as possible on one side and bolt it down and then use the gantry to slide up and down to get the second rail inline and then bolt that down and then just use engineer squares against the aluminium beam and side plates to make sure thats square

You are going to need to be able to square the gantry once the machine is up and running, by adjusting home positions for each end of the gantry. Whether you do that via software or manually (home one end as part of the usual homing sequence and then adjust the second end manually) doesn't really matter but you do need to be able to do this. Probably the easiest and most accurate way to check that the gantry is square is to use the machine to make four holes in a square pattern in a piece of suitable material (I use MDF and make the holes a firm fit for the shanks of a set of identical drills). Measure the diagonals and adjust the home positions for the gantry until those measurements are as close to each other as you can make them. Any machine which uses two motors/ballscrews on a single axis will need to be able to do this.