Abstract: A method for twisting a pair of moving strands uses a winder assembly 510, which is mounted on a first shaft 140 and rotates around a cylindrical drum 110. Twisted wire is wrapped in adjacent convolutions around an exterior surface of the cylindrical drum, which is mounted on a second shaft 150. The exterior surface is energized to advance the convolutions from its input end to its output end; and an unwinder assembly 520 is mounted on a third shaft 160 at the output end of the drum. The shafts are coaxial with each other and each is capable of independent rotational movement. The volume of strand material stored on the drum may be varied by changing the relative rotational speeds and directions of the different shafts. A twist in one direction is imparted onto the strand pair when the number of convolutions stored on the drum is increased; and a twist in the opposite direction is imparted onto the strand pair when the number of convolutions stored on the drum is decreased.