I am trying to remember how I made my wood screws. I know that I did not like the commercial ones that were available (this may have changed in the last 14 years) because the slots were wide enough to drive my B61 Mack through. IIRC, I would build up the head a bit with the mig, then take a plate I made with various sizes of holes and counter sinks and Swedge them in the plate, dome the top in the lathe and cut THIN slots.