Known splicing mechanisms generally have a cylindrical channel, or in certain constructions also a slightly conical channel, into which are inserted two yarn or thread ends which are to be joined. In the axial center of the channel an air inlet is positioned tangentially with respect to the channel wall and, through that inlet, compressed air is blown into the channel so that the two yarn or thread ends are jointly subjected to turbulence. In these known mechanisms, there is the disadvantage that the tangentially entering air produces a twisting movement which is increased on the yarn or thread at one side of the splicing chamber and is decreased or completely eliminated from the other side. Due to the parallel positions of the fibers, there is then a weak point with little or no tensile strength, an apparatus of this type being shown in Swiss patent No. 495,445. In addition, the yarn or thread ends spliced in this way frequently have projecting terminal portions of the strands which are left on the threads and which, during further processing through eyelets and thread guides, can cause considerable problems.