My only comment would be good luck. I'm not an accomplished machinist by *any* means, though... I bought roton rolled screws which are supposedly not hardened very deeply, and they kicked my a** trying to machine them with my south bend 9". I ended up rigging up a grinder and grinding them.
I also bought a ground screw off of ebay, and just cut it to length using a cutoff blade in a dremel. The other end was already machined and useable as is.
Anyway that's my 2 cents worth, you'll hopefully get better answers from those truly in the know...