Another lefty!! I have one of the left handed single wire cutters from Workshop Heritage, but I began with the one in the OP. I could never get a straight cut, but I don't think it had anything to do with me being left handed. I ended up putting multiple layers of tape on the slots to close up the cutting space (hope that makes sense). It worked, as long as I remembered to hold the other end of the soap loaf to prevent it from moving. I've never been able to cut straight with just a knife. FWIW, I can't draw a straight line to save my life.