in a machine for packaging pieces (T) of equal size, particularly tiles and bricks in general, provision is made of a rotary vice (1) apt to form regular packs of pieces being fed irregularly. Said rotary vice (1) comprises a pair of opposed jaws (3, 4) with a plurality of arms apt to perform in a discontinuous manner movements of rotation and of mutual approach and parting around and along the axis which joins the geometrical centres of said jaws, said movements being controlled in an automatic and coordinate manner so as to allow separately the gripping, the conveyance with rotation by 90° and the release of such pieces (T), one at a time and in rapid succession, from a conveyor belt (2) which feeds them irregularly to a conveyor belt (6) onto which they are fed arranged in packs.