Abstract: A system for transporting tube or bar stock along its horizontal axis comprising conveyor sections and a drive section each section containing a series of rotating drive assemblies. The drive assemblies contain a pair of frusto-conical rollers upon which the tube or bar stock rides. These rollers engage threads of opposite hands disposed on opposing portions of a driven shaft with respect to the axis of transport. Means for rotationally connecting and disconnecting the shaft and rollers such as locking pins or clutches are provided. Means for preventing the rotation of the rollers such as disc brake assemblies or stop bars which contact radially protruding members rotationally connected to the rollers are provided. When the rollers and shafts are rotationally connected and free to rotate, the work piece is transported.