A die assembly having a bending die and a clamp die. The bending die comprises one or more movable plates and a wedge plate. The bending die includes a channel formed in one or more of the plates configured to receive a pipe or other workpiece to be formed. The movable plates are movable between a first position wherein each plate is spaced from the adjacent plate a predetermined distance and a second position wherein each plate is compressed so there is less distance between the plates. Movement of the wedge plate from the retracted position to the engaged position causes the movable plates to move from the first position to the second position. Compression of the movable plates correspondingly reduces the width of the channel to help grasp any workpiece inserted therein.