According to Bob Patton's recipe, pressure flake it down until it's even and has a good center ridge, but leave the tip round and grind it. Set the tip on an antler or wood anvil, and support it against a block of wood. The example I saw, he used an antler rocker punch to take the flute off, hitting it with a heavy hammerstone. The punch was laying on top of the block that was supporting the point. He says that slow and heavy is the way to go.