Hebei Yida BGZL-40B3 steel bar straight screw thread processing rib peeling machine is the exclusive use rib peeling knurling machine for the straight screw thread connecting. It is mainly used in the processing/fabrication of the end of the structural steel bar. Positive And Negative Screw Thread Model Used in the occasion when the steel bar in the two sides both can not be turned but the lengths can be adjusted.