Planetary Roller Screws Planetary roller screws are a particularly precise and robust form of linear drive. Their construction design produces significantly higher load capacities and rigidity compared to other linear drives, such as ball screws (KGT). This is a direct result of the so-called threaded planets used in the design. The threaded planets serve as rolling elements between the threaded spindle and the threaded nut. Another great advantage of planetary roller screws is the wide range of possible leads they offer. The multi-start thread profile of the planetary roller screws allows total spindle leads of 0.5 mm to 50 mm.