Abstract: To permit selective needle projection, under control of a patterning arrangement, the needle jacks are made for rocking movement about an axis transverse to the direction of needle projection during knitting, and the camming system for the needle jacks is formed with two tracks, located one above the other (by a deeper cut, or camming elements of different heights) or, longitudinally staggered, one adjacent to the other, the cam tracks being arranged for selected projection of the needles to tuck or knit position; the needle jacks having either a butt projecting far enough to selectively engage either of the superimposed cam tracks, depending on the extent of rocking of the needle jack about the fulcrum, or the needle jack being formed with two butts, one on either side of the fulcrum, and selectively engaging the adjacent cam tracks, depending on the direction of rocking of the jack from a center position.