Two press brake machines each using a single, central hydraulic actuator are provided. The press brake machines are configured to operate separately or in tandem, depending upon a size of a sheet metal workpiece to be deformed. A locking device that may include an upper connecting block and a lower connecting block is provided on each of the at least two press brake machines to allow the machines to interlock when the machines are adjacent to one another and are operating in tandem. The upper connecting block may be “L” shaped to help provide the interlocking. Interlocking of the press brake machines during tandem operation helps prevent distortion that can occur in the upper and lower portions of the ram due to the press brake machine's use of a single, central hydraulic actuator.