... ,worm gear,ball bearing,oil seal,housing and ball screw 1.Model: RNK-0.5T,1T,2T,3T,5T ... Lifting Speed: 75 mm/min ~1800 mm/min9.Ball screw jack assemblies use small balls to roll between the ... less friction than worm gear screw jack and increase use life.10.Ball screw jack is more suitable to ... with frequently lifting and precise positioning.11.Ball screw jack stand loading capacity is 1/3 worm gear ...