There are two general types of screws used to create motion and power: Power Screws and Ball Screws.
Power Screws
Power screws are the simplest of these as they have only two main elements, the screw, and the nut. Considerations for application and selection of power screws include:
Ball Screws
Ball Screws utilize a series of ball bearings between the screw and nut threads so that movement is achieved through rolling friction Considerations for application and selection of ball screws include: