Abstract: A twist drill has a cutting member at the bottom, a shaft at the top, and a reduced-diameter root clearance region between the cutting member and the shaft. Cutting edges are provided at the transition between the cutting member and the root clearance region, and further cutting edges are provided at the transition between the shaft and the root clearance region. After a throughhole has been drilled using the cutting member, the drill is displaced laterally and moved along a circular path while it is still rotating. As a result, the cutting edges at the transition between the cutting member and the root clearance region countersink the bottom end of the throughhole. A similar procedure is employed to countersink the top end of the throughhole using the further cutting edges at the transition between the shaft and the root clearance region.

Abstract: The chiplessly formed open end spinning rotor (1) has, in the region of its collecting groove (11), a surface which has not been contacted by shaping tools. To produce it, a pot (3) is first made by stretching and stamping of flat material. This is then secured in its radial position independently of shaping tools. The peripheral wall of the pot (3), in the region between the later collecting groove (11) and the open edge of the pot (3), is upset inward by any optional kind of plastic deformation and the region later to be the collecting groove (11) by unsupported plastic deformation ["against air"].

Abstract: At least the collecting groove surface of a chiplessly formed, open-end spinning rotor is not contacted with shaping tools as the groove is formed. Such collecting groove may have a surface including a number of smooth, uniformly distributed islets formed thereon during initial production of an intermediate product pot. To produce the rotor, a pot is first made by stretching and stamping flat material. The pot is then subjected to plastic deformation, such as roll pressing, to affect a peripheral wall of the pot to form the collecting groove between such peripheral wall and a bottom of the pot. Such plastic deformation may further optionally be accomplished without interior support of the walls thus formed, with the result that such undistributed slip walls also have smooth, uniformly distributed islets thereon.