▶ Watch the step-by-step video (YouTube)
The stitches will look different from those made with a diamond chisel, so try various ways of punching the holes to get the stitch you like.

Punch the holes with the diamond chisel, leaving the corner hole, then make the corner hole alone with a round awl.
▶ Watch the step-by-step video (YouTube)
The stitches will look different from those made with a diamond chisel, so try various ways of punching the holes to get the stitch you like.