All steel, no welding, 2000x1300x250mm

[toomast]

Something fresh and new!

Your calculated weight numbers seems to be very low! 10mm and 15mm steel is heavy stuff...

My experience with laser and plasma cutting tells me that positional accuracy is always good but edge is never 90 degrees. Plasma is worse than laser. It also gets worse with thicker materials. Most certainly you will have to use straightening tools since sheets are not flat. But good rubber hammer will get it fixed :D
You have to somehow make the openings for M10 nut pressfitted otherwise the nuts will fall out. That especially when you assemble the gantry...or you have another solution for it?

As for the rails...somehow I have a feeling that you will end up with HIWIN stuff.

[Blackrat]

Please dont go with the round rails !

it will ruin what is looking like a nice design

thats all i have to say :S