Abstract: An internal frame carrying vertical rolls of a roll set permanently remains in the mill. The frame consists of spaced-apart cross members tied together on each end by a yoke member. Clamping plates hold the frame down in the mill. Pass line adjustment of the vertical rolls is done through vertical movement of the frame. The yoke on the operating side is removable and is raised and lowered for roll set changing, and is equipped at its top with tracks which in the removable yoke's lower position form part of a rail system in the roll set changing operation. Pins and cylinders hold the removable yoke to the cross members. Stooling pins are automatically engaged in the chocks of the vertical and horizontal rolls forming an interlocking roll set for its removal from the mill.