In the operation of twisting spindles, the movement of one yarn component through the ballooning limit is structured so that the sum of the contact time between the yarn component and the limit has a ratio to the total running time in a ratio of 1:2 to 1:200. The yarn/limit contact time is followed by a non-contact time in a ratio of 1:2 to 1:20. Also claimed is an assembly with at least one twisting spindle with an undulating ring near the yarn balloon for the yarn component to pass through or round, where the side in contact with the yarn has an edge structure which deviates radially from a circular shape. The ballooning limit has an inner cylindrical surface to make contact with the ballooning yarn component at intervals. The yarn is formed into lateral waves structured to make the required contact and non-contact times, and the wavelength of the yarn gives a standing wave within the limit. The ballooning limit can also have coils in a single- or multi-pitch spiral to give the contact and non-contact times with the yarn. The pitch of the spiral coils is in a ratio of more than 10:1 to the pitch of the yarn passing round, and the coil thickness has a ratio of less than 1:3 to the gap to the neighbouring coils.
