Linear Motion Tips covers news + tech info on motion transfer components, actuators, guides, conveyors, drives, rail systems, bearings and linear motors.
Plain bearing linear guides (which use sliding instead of rolling contact for linear motion) can have boxway, dovetail, or shaft-and-bushing geometery.
Behold the screw drives on this 3D printer's vertical axes and the belt drive on the horizontal ... giving assist on the horizontal are linear guides in the form of bushing plain bearings. Think there's no advanced engineering in these round shafts? Think again.