1075 - Heat to just a little above non-magnetic and quench in canola oil warmed to 120°F. Temper for 2 hours at 400°F, let cool and put back in to temper for another 2 hours.
To make the taper, start with a single bandsaw cut down to the depth you want. Then take an old handsaw, grind the teeth off on the bench grinder and glue on or apply some sticky backed sandpaper to one side of the saw blade. I used this simple set-up to basically just slide into the cut and sand in the taper on both sides until the tang fit nicely. This was actually my first time making a partial tang knife let alone one with a tapered tang.