A dressing tool produces a plurality of first radial sections in a first flank of a first screw channel in a grinding worm, and a plurality of second radial sections in a second flank of a second screw channel in the grinding worm. Each radial section extends only a portion of a total radial height of the respective flank, the portion being less than the total radial height of the respective flank. Each first radial section in the first screw channel is radially displaced with respect to a corresponding second radial section in the second screw channel.