Originally Posted by
stevespo
A small commercial 4 or 5 axis mill is going to be pricey, and trying to build one rigid enough to tackle aluminum with precision is going to be complex. The 8020 builds are certainly capable of occasional work in aluminum, but if this is something you're going to do on a regular basis - you probably want more mass (steel/iron), different spindle, etc.
If you really want to make a mill, then go for it. It is going to be a long project and require a lot of research, sourcing parts, etc. It may take several iterations before you get the engineering elements right to produce the kind of quality you're looking for. A great learning experience, but it will be a while before you're making anything.
If you want to make and design parts, then consider outsourcing them and eventually pick up a small (used?) VMC and you can do the work yourself.
Steve