1200mmX900mmX170mm 4axis cnc

[routercnc]

Advice needed.

I repost here since at my other thread I didn't get any respond.
I am thinking for something like that for my X axis, I prefer to build it bolt on ,with minimum welding, since it is one man job and better to handle, plus I want to avoid metal stress,that I am going to get with welding.
X axis is made from 90x90x900x4mm steel structural sections
At front and back of the steel tubes I will place two steel plates 5mm to stiffness the structure ,also the two plates ,left and right, are going to be 5 -7 mom.

With 2 off 90x90 sections stacked on top of each other with what looks like another 90 mm gap the gantry is going to be very tall. This means the loads going into the top rail are along way from the X axis ballscrews (which react that load) and you are reliant on the sheet panel sides to do the load transfer.

Is this height because you need lots of Z travel?

Whilst yes this would work, I think there are more elegant steel fabricated solutions. For example this one from 'Toomast':


There's this one too:

Both involve welding so as you point out care is required during construction.

More popular is aluminium extrusion for the gantry because it is easier to work with:


For wood working, guitar making and occasional aluminium I would say all the above are suitable designs.