the formed corespun yarn c initially a covering yarn is threaded through the lower set of rolls 98 into the lower guide passageway 31 outward into the cylinder 45 and through the eyelets 46 47 when a tube is used as described above vacuum may be used for threading the yarn otherwise a mechanical threading apparatus is used the covering yarn 12 is drawn in wrapping engagement with the core yarn 63 and the resulting corespun yarn c is drawn upward through the upper guide passageway 40 to the upper set of draft rolls 99 where it is wound on the core of a take up roll 100 the spindle 20 is rotated at a high rpm ranging from 50 000 to 60 000 rpm the upper set of rolls 99 pull the formed corespun yarn c upwardly while pulling the core yarn 63 and the covering yarn 12 from their respective yarn packages 61 11 as the spindle 20 rotates the covering yarn 12 is centrifugally forced against the inside wall of the cylinder during high speed spindle operation the cylinder 45 and eyelets 46 47 guide the covering yarn 12 to a restricted diameter for preventing breakage of the covering yarn the covering yarn rotates with the cylinder and is forced into wrapping engagement with the core yarn to form the.