While I am stitching I am getting slanted stitches on the back and straight stitches on the front. I am using 4mm diamond chisels from weaver with .6mm thread. I am stitching with the holes slanted up and away from me. The side that I punched holes from is on the right and that is also what I am calling the front. I start in the first hole, even up my thread and start stitching towards me. I place the first needled through the back or left side and catch it on the right side, make a cross, pull it through, slight pull back on the threads so I can go back in the hole from the left over the other thread. I then cast the thread over the needle as it comes through and then pull tight. The stitches on the back look good but the front are straight as can be. What am I doing wrong?