heated nip roll in an embodiment the two nips are on opposite sides of a larger central cooled roll positioned between the heated rolls in an embodiment the reaction forces between the rolls are measured and controlled at each end of each of the 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 application_number US 990404 A description referring now to fig2 an exemplary the apparatus 100 according to the present invention is illustrated in this figure the stem web 102 having a backing 104 and stems 106 thereon is maneuvered over idlers 108 and into contact with a heated roll 110 the stem web 102 is nipped between first heated roll 110 and cooled roll 114 within this nip 116 the stems 106 are deformed so as to provide partial caps 118 it is to be noted that after emerging from nip 116 the stem web 102 remains in contact with cooled roll 114 in a region 120 which is preferably at least 20 more preferably at least 25 and even more preferably 30 of the circumference of cooled roll 114 it has been observed in the development of the present invention that under certain conditions the rate of cooling becomes a limiting factor therefore in preferred embodiments the cooled roll is deliberately larger than the heated rolls so that it has.