Very nice, I am a couple of days behind you in your build. 10 minutes till the Z nut locks finish then I can finish the middle section. After that I finish the Z section. This is my first cnc build. I have owned my Printrbot Simple Metal for about a year now. I have mainly been using google sketchup to make my own little parts to help me with everyday life. I came across mpcnc by accident on thingsverse, I printed a corner block as a test to see how accurate my printer was and it fit perfectly. Two days later I had ordered the parts bundle and had quite a few parts printed. I didn’t put much thought into a color scheme so I kept on printing with what I had on hand, glow in the dark pla. Kind of strange but it seems very strong. My plans are also to build 24 x24 machine. I look forward to following your progress.