A conveyor system for transporting a work piece from a beginning point to an end point in a longitudinal direction with at least one process step applied in between to such work piece is provided according to the invention. The work piece is propelled in the longitudinal direction over a combination of grooved rollers and conveyor belt units in series. Grooved guide means with, e.g., V, U, or square shapes that are machined into the surface of the rollers prevent the work piece from moving laterally as it is transported in the longitudinal direction, and maintain precise spacing between a plurality of work piece strands undergoing simultaneous transport by the conveyor system. The conveyor belt unit located between the grooved rollers inhibits rotation of the work piece as it is transported in the longitudinal direction. This conveyor system is good for treating the entire exterior surface area of the work piece in a uniform manner, such as coating the surface of rebar, dowel bar, hollow tube, or pipe.