A cutting die head that can be set and/or reset without an external mechanism. To this end, the die head includes a die body including a plurality of radially adjustable blocks, each block having a cutter mounted thereon and a radially outwardly facing cam surface. A sleeve surrounds the die body and has an inner surface. The inner surface has a plurality of cam surfaces arranged to communicate with the cam surfaces of the blocks such that axial movement of the sleeve results in radial movement of the blocks. In one embodiment the sleeve is caused to move axially by fluid pressure.