Abstract: A cylindrical die for a pellet mill for animal feedstuffs is releasably clamped to a rotatable die holder by means of a series of clamping segments disposed in a recess at the end face of the die holder. The recess has a radially outer conically diverging surface which cooperates with conically shaped outer surfaces on the segments to produce clamping of the radially inner faces of the segments on an end portion of the die.The clamping segments are urged into engagement by springs acting on rods connected to the segments and are disengagable by means of a series of hydraulic rams which can be actuated to oppose the force of the springs. The direction of the forces is chosen to be at an angle to the axis of the die holder so as to cause the clamping segments to follow the surface of the recess and to move radially away from the die during disengagement. The angle chosen is preferably the angle of divergence of the recess. In a modification centering segments are interdigitated with the clamping segments.