Viperia, I believe that the rotational speed of a router is much to fast for machining aluminum. I have a mill and machine aluminum at approximately 300 RPM. The recommended router (Hatachi) for Joes CNC router has variable speed of 8,000 to 24,000 RPM.
After I get my Joes router done I plan design a motor mount system for a DC motor I bought on eBay. I will buy a 90 Volt speed controller and try to machine aluminum. The collet mechanisum will be challenging.