Hi Ron,
If only it was that simple.
Unfortunately, because there is more than just one way of doing just about everything, there is huge difference of opinion on which is the best way so you have to shop around choosing the best bits (in your opinion) from here and there.
I built my own CNC from scratch and spent many months looking at every design I could find on the net, hoping to learn from others mistakes, finally settled on my design and away I went. It turned out pretty well and I can produce good stuff but If I was starting again, with what I have learnt since, the design would have some major differences.
Reading this forum will give you a mine of knowledge, some things being what to do and others being what not to do but IMO the only real way is to jump in both feet. Personally I don't think Routing and Plasma share any common ground as far as machine design is concerned and two machines would be a better option if this is what you are planning to do. Perhaps constructing a cheaper and more basic machine would give you the experience to know exactly what you need for a quality build.
Don't know if my ramblings help at all
Tweakie.
