Commercial quality anti-backlash lead screw nuts have a minimum preload of 0.19 lbs. to a maximum preload of 11.1 lbs., with internal threads of 3/16-20 to 5/8-10, and are manufactured in Turcite X engineered thermoplastic material. Precision quality low drag torque anti-backlash nuts are manufactured in Polyacetal engineered plastic including an integrally molded flange. The drag torque in the mini series nuts is 0.5 oz-in. while the light, medium, and heavy duty nuts have a drag torque of 0.5-2 to 3-7, 1-3 and 2-6 to 3-7 oz-in. respectively, with load capacities from 5 to 350 lbs.