A method for capping a stem web including passing the stem web through a first nip against a first heated nip roll so as to partially cap the stems; cooling the web; and passing the stem web through a second nip against a second heated nip roll to completely cap the stems to a diameter “D”. In preferred embodiments the two nips are on opposite sides of a larger central cooled roll positioned between the heated rolls. Preferably, the reaction forces between the rolls are measured and controlled at each end of each other heated rolls. The invention is particularly adapted to making abrasive particles that are attached to a driving mechanism via headed stem fasteners formed by the method.