I am at the stage now where I have collected everything that I need to build a CNC router apart from the steel and I am formalising my final designs. The rough diagram was done in sketchup and is really just to give myself an idea of what the final build may look like so that I can try and predict problems that I will encounter before assembly. One thing that I am worried about is preventing dust from getting into the main leadscrew. There will be a dust extraction system added to the final build and I will cover up as many of the gaps as possible but I still anticipate it being a problem.
One thing I wanted to ask was about the leadscrew protection that I have seen on lathes. I think that called the CS guards or somethng like that. They look like a spring of coiled plastic strip that compresses and expands as the nut moves back and forth thus giving a certain level of protection to the screw. I have also heard however that these can be bad as if something does get into the thread then you can never get it out.
Anyway I haven't ordered any metal yet so there is still plenty of time to make a design change.