welding steel base or just getting aluminium extrusion

[Desertboy]

I had recesses on most of my plates which is why I had to have them cnc'd out I know Joe did it in his amazing thread with a router but that's beyond me lol.

I put recesses in my gantry plates so the extrusion sits 5mm into the plates (20mm thick plates) and I will do this on every router I ever build again, never seen anyone do it but I've took a lot of commercial magazine printers apart (my router is made from one) and their gantries are always recessed.