Abstract: The present invention pertains to a screw essentially comprising a plurality of bulges disposed on threads of the screw and unengaged with a shank; whereby a consecutive extrusion path is formed between the bulges and the shank. Herein, while the bulges facilitate the screw threads to efficiently chop fibers of the object into debris and render the screw to easy drill into the object, the extrusion path smoothly guides and extrudes the debris therealong. Thus, the present invention conduces to decrease the drilling torque resulting in a speedily screwing; moreover, the bulges also allow the unsevered fibers hugging therearound to enhance the screw firmness inside the object.