I use an exact knife handle (the one that looks like a screw driver handle) and a blade ( I'm not sure of the part number) but its the one with a curved radius to the cutting edge that is convex, not concave, this allows you to cut with just the point. Doing pen, and ink, drawings using cross hatching techniques, for shading is great practice. Cheap plastic spoons work well for practice, as well. Plastic spoons are curved, and similar in density to horn or ivory. Good luck.
Hungry Horse