A replaceable milling head rotatable in a cutting direction about a longitudinal central axis, the central axis defining a forward direction and an opposite rearward direction, has a forward cutting portion and a rear threaded coupling portion for coupling to a shank. The cutting portion includes two or more key actuating portions which assist in mounting the milling head onto the shank. The cutting portion includes a plurality of helical chip flutes alternating with cutting edges. At least one or more of the cutting edges and flutes extend axially rearward of at least a portion of the key actuating portions.