A mold device is described for use in a mold having a plurality of tread molding segments. Each tread molding segment has an end face for mating with an adjoining segment. The mold device includes a piston located on the segment and is actuated by the opening and closing of the mold. The piston is positioned within a first chamber and has a plunger end in communication with a working material and a spring. Each of the mold segments further includes a retractable blade assembly having a distal end in fluid communication with a second chamber. The first chamber is in fluid communication with the second chamber. Closing of the mold compresses the piston, forcing the working fluid to transfer from the first chamber to the second chamber, actuating the blade assembly.