Abstract: A method of simultaneously cutting the surfaces of a set of a plurality of rolls made flush with one plane, disposed at equal angular intervals, and forming a central caliber therebetween, by means of a cutter provided with cutting tools in the same number as that of the rolls. The cutter holds the cutting edge of the cutting tool in parallel with the cutter shaft and adapts the cutting edge to face the just front side of one of the rolls for the purpose of cutting. In cutting, in addition to the movement of the cutter in the axial direction Z and circumferential direction .theta., the cutting tool moves in the radial direction R of the cutter shaft. Thus, the cutting edge 21a' is kept facing the roll shaft at right angles all the time in spite of positional change in the circumferential direction .theta., whereby simultaneous and continuous shaping of not only the caliber surface but also round parts 10b on both sides of the shoulder and 120.degree. surface is made possible.

Abstract: A large-diameter welded steel pipe having a straight seam and tab plates attached to its ends as extensions of the seam is laid along a setting line with the seam upward. An apparatus for treating the ends of such a pipe has a tab plate cutting unit and a bead removing unit. The tab plate cutting unit cuts the tab plates off with a torch. The bead removing unit removes the weld beads on the inner surface of the ends of the pipe by cutting them with a rotary cutter.