the roll however it increases the roll weight if this cover is remachined u2014 which is done at regular intervals u2014 the roll weight also decreases and hence the sag a further change in the sag results in the case of variations in the operating temperature on account of the modulus of elasticity decreasing with increasing temperature depending on the intended calendering result the temperature of the heated rolls and the line pressure in the calender are increased while the temperature of the heated rolls made of shell chilled cast iron is influenced directly by means of a liquid or gaseous heat transfer medium which flows through the roll bodies an increased pressure increases the flexing work in the resilient covers the frictional heat produced in this way leads to increases in the temperature of the covers and of the roll bodies for this reason these are often fitted with cooling facilities the two effects are the reason why it is not possible to design the rolls in a roll group in such a way that said rolls have precisely equal sag under all operating conditions and for the entire period of use of the rolls although the above described inventive production method makes very precise production possible two extreme situations may be described for the roll.