An apparatus for producing a yarn including reciprocating twisting stage (4) adapted to simultaneously twist one or more slivers to produce one or more twisted strands, including one or more rollers (6a, 6b) arranged to move reciprocally (B) along the axis of rotation of the roller(s) to input twist to the sliver(s), and control means enabling control and variation of one or more of: (a) rotation speed of the rollers(s); (b) extent of transverse movement of the roller(s)s; or (c) speed of the transverse movement of the roller(s), to vary the twist imparted to the sliver(s) or strand(s).