You can make tapered threads traditionally. 1) By making tapered swages for the various sizes, which involves making a rounded chisel, and cut the threads into the swage, top and bottom, making sure they line up, then forging the taper on hook etc., place in bottom swage, line up top swage and tap, then clean up with three cornered, or tapered file.
Sounds like a lot of work, but If you are going to make a lot of items, that's the way to go.
2) Forge your taper on item and cut threads with three cornered or tapered file.