used in the practice of the method taught herein is a large rotatable drum in the figs the bundle in the process of being wound is indicated by the numeral 20 while the drum is indicated by the numeral 22 the drum has longitudinal vanes 24 the size of the drum is such that the tangential distance between the tips of adjacent vanes 23 is equal to or slightly greater than the desired length of the filament bundle the drum is rotated around its own axis and a supply of hollow filament yarns from one or more supply packages are wound helically around the radial spokes 24 a traversing mechanism 26 is provided so that alternating layers of windings traverse in opposite directions and create a winding pattern with a multiplicity of yarn crossovers filaments are wound onto the rotating drum as shown in fig2 a and 2b there can be multiple supply packages 28 of hollow fils in order to shorten the time necessary to wind on the required number of turns the winding pattern must also provide a level wind traverse so that a pattern of left and right hand helices with multiple crossovers is created as shown in fig2 b when the required number of turns have been applied they are roped together by sliding axially along the drum as shown in fig3 and 4 this step can be made easier if there is a provision for retracting the blades 24 to reduce their diameter slightly or if they are tapered toward one end with a slightly smaller diameter at one end of the drum than.