is formed into a loop 42 39 that passes through the bight portion 32 39 of the right loop 24 39 and as the material is advanced the bight portion 44 39 of loop 42 39 is open and below the penetration point 30 39 of the next successive stitch of the right needle thread 18 39 thus the bight portion 44 39 is penetrated by loop 24 39 of the next stitch formed by thread 18 39 thus the right needle thread 18 39 and the right looper thread 48 39 form a standard type 401 stitch this first row of type 401 stitch is formed through only the lower ply 12 39 of material and follows along the edge 14 39 of the upper ply of material 10 39 the middle and left needle threads 20 39 and 22 39 cooperate respectively with middle and left looper threads 50 39 and 52 39 in the same manner as described above for right needle thread 18 39 and right looper thread 48 39 to form standard type 401 stitches that extend through both the upper 10 39 and lower 12 39 plies of material a cover or spreader thread 60 39 is cast on the upper surface of the superimposed workpieces 10 39 and 12 39 and interlaced between the needle threads 18 39 20 39 and 22 39 such that it follows a serpentine path and ties the three standard type 401 stitches together as the stitch is being sewn the spreader thread.