A newly designed high speed automatically lubricated lockstitch zig zag machine capable of producing a regular zig zag stitch and a three step zig zag stitch by a simple lever adjustment without needing a cam change. The double point sliding block mechanism maintains excellent feeding performance and a triple step planar linkage mechanism easily provides accurate needle vibrating motion at high speed and stitch mode change over between one step and three step zig zag using a lever. The machine is well suited for decorative stitching on innerwear, foundations, swim suits, towels or wherever a high quality zig zag stitch is required.