Can someone describe what range of bits one should buy to carve into wood/acrylic/aluminum? I have no previous experience and I would like to start with the right foot. Even better if you can point to an amazon item. And even more awesome if you could give an idea of the speed needed for each material. My router is a 400w spindle from ebay with ER11 attachment and at 48v should reach 12000rpm. Thanks.