Roller thread drives consist mainly of a threaded screw and a threaded nut.Between threaded screw and threaded nut several thread rolls are arranged parallel to the axis. Roller thread drives stand out for their high load capacity and stiffness.Likewise very small pitches can be realized.As with ballscrews, rotational speed depends on length and diameter of the threaded screw. With appropriate greasing and assembly an approximately three-fold rotational speed and lifetime of ball screw is achieved.

 

Dovetailslide prevents the carriage from lifting off by slanting the side faces. Adjustment is made possible by a screw adjusted gib strip. Advantages of dovetailslides are high load capacity and precise guiding (if well adjusted) Sliding and static friction that do not appear with bearings such as ball bearing slides or crossed roller bearing slides are disadvantageous.

 

Owing to good rolling features (they are lacking static and sliding friction) they are preferable to conventional guidings such as dovetail slides. Backlash free linear translation is achieved by precise adjustment. However the load capacity is not as high as with classical gliding guides.Balls roll between two precisely ground and hardened sides. This corresponds to the principle of a ball bearing. The individual balls are lead through a ball cage in order to prevent obstruction. Ball bearing slides are finite guiding mechanisms where the balls cover 0,5-times the way of the translating object.