A yarn package structure that includes a package support having a main body of yarn, a yarn transfer tail consisting of a plurality of helical turns leading to said main body of yarn, a plurality of circumferential turns of yarn located in a circumferential stringup groove adjacent one end of the package support leading to said transfer tail, and a surface cavity on the package support intersecting the plane of said stringup groove. A means for pulling the circumferential turns of yarn over the end of the package support is secured by the circumferential turns of yarn against the package support.

A spindle, particularly for draw-twisting machines, designed for taking-up a detachable underwinding crown which can be placed on the spindle so that no rotation relative to the spindle occurs. The underwinding crown is provided with vertically arranged fingers or rods forming envelope parts for taking up a thread during the underwinding phase and with an upper limiting ring surrounding a tube of a bobbin placed on the spindle. The outside diameter of the ring exceeds the envelope parts. The spindle is designed for taking-up the upper limiting ring of the underwinding crown which is provided with elastic snap-on holding means, and is further provided with spreading means for spreading the elastically deformable envelope parts. There is also provided a lower limiting ring the outside diameter of which exceeds the envelope parts and which contains at least one recess for taking-up the free lower ends of the fingers or rods forming the envelope parts.

A radially expandable endcap adapted for mounting upon a mandrel of a collet of a forming package winder. Other aspects of this invention include a collet and winder including the above endcap and method for winding strand using the same. Another aspect of the present invention is a collet having an expandable mandrel on at least a portion of a first end of the collet proximate an operator and distal to a second, opposite end of the collet mounted upon a support Other aspects of this invention are a winder including the above collet and a method for using the same.

A radially expandable endcap adapted for mounting upon a mandrel of a collet of a forming package winder. Other aspects of this invention include a collet and winder including the above endcap and method for winding strand using the same. Another aspect of the present invention is a collet having an expandable mandrel on at least a portion of a first end of the collet proximate an operator and distal to a second, opposite end of the collet mounted upon a support. Other aspects of this invention are a winder including the above collet and a method for using the same.