The challenge of machining aluminum with the handibot is twofold; ideally you would want a very rigid tool with a spindle capable of turning at around 900 rpm (vs. 9000rpm on a handibot router). This can be overcome by programming your tool to make shallow passes (0.01") at a high feedrate. However, copper would be even more difficult. The high speed of the handibot spindle would most likely cause the copper to heat and gum up on the bit. If you're going to take a crack at it I'd advise using a sharp, new bit (the onsrud O-flute bits are good for this type of work: [
store.shopbottools.com]) and a feedrate of 4 IPS. Keep your pass depth around 0.01" and use a lot of lubricant.