1.The cutting edge is used the high-quality ultra slight grains of alloy material, which is suitable for opening hole in rusty stencil plate punch earnestly and maternally in cold hard metal,which has fine results and can be cut continuously.
       
The design of edge department is unique, whose edge of knife is adopted the asymmetrical design, which cam be cut hierarchically. It has spiral heat and power plant sharpen trough, punch feed to be brisk, belonging to quality tapping cutting tool.