Friction spinning is a spinning system in which the yarn receives its twist by being rolled along the longitudinal axis in the nip between two revolving surfaces.
The optimum twist is a term used in spun yarns, to describe the number of twists that gives the maximum breaking strength or the maximum bulk at strength levels acceptable for weaving or knitting.
OPTIMUM TWIST DIAGRAM
S-Twist Yarn is a left-handed twisted yarn. See Z-Twist.
Singles yarn is the most simple strand of textile material suitable for operations such as weaving and knitting. A singles yarn formed from fibres with more or less twist; from filaments with or without the twist.
Z-Twist is a term used to describe a right-handed twisted yarn, in contrast to S-Twist.