The machine adopts circularly oil-offerings, little oil-consuming, further improved capability quantity of base line confirming windows, you can confirm the quantity of the base line by exterior adjustment of thread, through the right and left self-governed spring as well, with two straight needles, self-lubricating vertical-axis rotating hook for catch thread loops and sliding can thread take up, self-lubricating can produce two lines of lockstitch, serve for the purpose of sewing shirts, uniforms, jeans, overcoats, etc. applied to a wide range of sewing materials, synchronized feed by needle and feed dog can prevent slippage and puckering between layers of materials, suitable for stitching shirt, uniforms, underwear and jean, etc.