DIY CNC Milling Machine Build - (Part 1) - CNC Mill CAD design and the Y axis

DIY CNC Milling machine build. My objective for this project is to design and build a CNC milling machine without the need for any machining of the parts. Ordinarily, building a mill requires a much bigger mill to get the axis surfaces flat and parallel. By using aluminum tool plate (which is in theory pre-machined flat) and bolting the critical components rather than welding, it should be possible to avoid any machine work. After all, I'm building a mill because I don't have one! Linear rails and ball screws are the cheap Chinese 20mm style that you can find on eBay etc.