Abstract: A zero clearance, backlash free, adjusting mechanism wherein a multithreaded helical member is constrained against movement within a movable support by means of oppositely disposed concentric threaded members separated by a concentric torsion spring. Opposite ends of the torsion spring are captivated by respective opposite concentric members. One of said members being fixidly, slidably mounted within said movable support. Rotation of the helical member forces the two concentric members apart along the helix forcing the members into a zero clearance position effective to prevent any wobble or yawing movement of the helix and thus eliminating any backlash along the helical member. A U-shaped clip surrounds the movable support so as to retain the assembly effective to prevent accidental dislodgement or movement of the concentric members.