Method for automatically controlling spinning rolls

A method for the automatic control in a spin rolling process of the set positions of spinning rolls in relation to a cylindrical, tubular workpiece in an opposed roll spinning lathe, said method comprising arranging first, second, third and fourth pairs of rolls in the spinning lathe in successive, axially spaced relation to form respective first, second, third and fourth rolling stages, each roll pair consisting of one inner roll and one outer roll, supporting each roll on a holder on a carrier so as to be radially adjustable in relation to the workpiece, said pairs of rolls being arranged at an equal circumferential spacing about the workpiece with the roll pair of the first rolling stage placed diametrically opposite the roll pair of the second rolling stage, the roll pair of the third rolling stage being angularly offset by 90.degree. in relation to said first roll pair and being diametrically opposite the roll pair of the fourth rolling stage, relatively displacing, during the spin rolling process, the pairs of rolls and the workpiece to produce relative translatory and rotary motion therebetween, continuously measuring the radial forces acting on the rolls during their displacment to their initially set positions and during the spin rolling process, comparing the radial forces at corresponding rolls of the respective opposite pairs of rolls and if a permissible differential force is exceeded radially displacing the roll of the preceding roll stage to compensate for lack of force equilibrium while keeping the other roll of said corresponding rolls in its initial radial position.