In order to machine aluminium or even steel, I'd need to significantly up my game on my small router. At first my concept was to keep things simple and cheap: I'd use a home aquarium pump (from ebay), with variable debit to create an oil cooling system on the machine. The next part was to make an coolant (oil) collector. The collector was made off two planks of pressed wood glued together and engraved to have a converging profile, a bit like  a sink really.