I am looking into mills (bits) as well. Just got the DW660 too. It will accept either 1/4″ or 1/8″ shank mills. The link you posted is for mills with 3/8, 1/2, 5/8, 3/4 inch shanks. It came with a simple roto-zip style mill that should cut foam board or wood at least. I plan on using thick foam board to practice on. Still a lot of terminology to learn.