I was a few years ago aware that some people even built their own small CNC machines. And having seen and read a lot, I was ready to try for myself.
The first CNC machine I built was a converted Proxxon Micro milling MF 70. A fine little machine with a relatively good accuracy, but not very fast and with a very modest size of the cutting area. So when I'm in a forum so that there was a another home builder that had set his for sale, I went for it and did some further developed on it. It has a cutting region of about 50 x 50 cm which is fine for what I built. I would still like to see it run a little faster in x and y axis, to avoid melting when I cut in plastic materials. So when I get time, I will change the control and raises the voltage on my stepper motors, to get a little more speed.
I chose to use the software '2D cut' and '3D cut' from the company Vectric.com. And I can definitely recommend these programs, they very easy to use, and can virtually everything you need. To control the CNC machines I have chosen the software MACH3 which is used by many CNC do it yourself builder. This is an old program, and takes some time to get familiarize with.