Abstract: Frustoconical portions of a blade blank are ground only along their external periphery so that the grounds are cylindrical. The frustoconical portion form openings as well as of 20.degree. to 30.degree. with the generatrix of the cylinder. The blades can be ground a number at a time in the form of a stack with the disk portion. The resulting blades are mounted on the spindles of a ring spinning or ring twisting machine to cut the threads to turn the last thread on spool or bobbin and lower turns on a collecting region of the respective spindle.

Abstract: A contact roller is shiftable in two mutually perpendicular directions so that it can press the cut end of a web, e.g. of thin scratch-sensitive film, against an empty roll in a waiting position while maintaining contact with the roll being completely wound in the winding position. The empty sleeve and the wound roll are mounted upon arms of a turret or the like so as to be swingable about a command axis but independently of one another.