This Steel Rod Necking Machine (called Steel Pipe Reducing Machine), SJ42 Type, is reduced diameter of metal workpiece without cutting and peeling. Efficient (Process speed is 3-7P/M), stable, high smooth and polishing surface, easily operate and saving raw materials. It could enhance the density of steel, rebar, bolt, and some any other metals so that not reduce the material strength, toughness and other physical properties of material at the same time get raised and saving the material for the lost in cut less and peeling. The machine is the new model assist of thread rolling machine. It is the best choice of processed mine anchor, anchor building, anchor bolts, stud bolts, long pole screw and any metal diameter processing.