Mk2 extrusion router

[RobC]

So I've given up trying to make my current first build accurate and it's just not feasible (ZeeflyBoy has inspired me to build a better one). I didn't think of the old 'if you cant make it perfect make it adjustable' when I was building it and so now I've been trying to add in adjustable features which sort of work but I'm still way out on the z-axis. With this next build I'll be ditching the rather heavy 80mm steel box and going with Ali extrusion. This is the section which I've got least experience with. I'd like to make this a question.

1) Which extrusion size would be applicable best for a roughly 1000mmx500mm which will only be cutting wood and aluminium, I won't be factoring in steel machining to this. The end pieces will be 20mm aluminium plate bolted right into the extrusion core. Also to add the gantry span would also be extrusion, what would be a good size to work with 20mm hiwin rails.

2) So far I've gauged I'd like a double such as 4080 such as here
http://www.aluminium-profile.co.uk/a...KJN993130.html

3) -I'll be using 20mm Hiwin rails
- 20mm ballscrews

I'm yet to fully piece a design together as I'd like to get the critical structure understood prior to that. I'm in the UK and would only like to order from the EU or the UK so no China (Customs love my address).

And here is an image of my current setup, I've had such bad luck and became depressed with the issues and never went further with my great plans of wiring in all the sensors, such as temperatures and max/min travel with lovely steampunk style gauges to let me know the values on a machined panel. I will have to move the lathe, again