1200 x 800 Gantry Router Build

[reotilemarine]

I have been a long time lurker on here reading the build logs and trying to get as much knowledge as I can about the subject of CNC routers. I am now in a posiiton where I would like to build a CNC router and look forward to feedback from you all for my ideas.

I am looking to build a CNC router to mainly cut wood / carbon fiber. I build a lot of RC models as a hobby and this this will aid in making them. I am constrained to 800mm frame width as it has to fit through a doorway into my workshop. I have chosen 1200mm length to maximise bed space. I am hopefull for 1000 x 600 workable bed space however I accept this will be limited by design.

The dimension that I think may add to the complexity of the build will be the Z axis. I would like to ideally have up to 300mm useable travel as I would like to use the router for machining plugs for composite moulding and as such require the large Z axis. Therefore the router has to be capable of reasonable quality 3D surfacing over the Z axis travel.

I would like to base my design along the lines of Joe Harris's / AndyUK

Some initial thoughts of materials would be

80x80x4 for the box section framework
60x60x4 adjustible bed
1610 ball screws for X, Y and Z axis with the Z axis connected to the motor with a HTD belt to allow for different ratio options.
X axis I am hoping to drive two ball screws with one motor and a large belt connecting the two together.
Linear rails for all axis
Expoxy leveling for the X axis
Gantry 90x45 in an L confuguration


So that is a brief summary for the beginnings of my design. I would be greatful for feedback on meterial sizes, z axis limitations for 300mm usable travel and any other glaringly obvious problems with me chosen materials.