Purchase some thick 12-inch steel screws. It is important that you purchase high quality screws for this task; tree steps must be able to support the weight of the hunter climbing them.
Measure 2 inches in from the tip of each screw using the ruler and mark this point with permanent marker. This will be the portion of the step that is screwed into the tree.
Measure 3 inches in from the 2-inch mark on each screw with your ruler; mark this point with permanent marker. This will be the point at which the screw bends out, away from the tree for you to step on.
Use the pipe bender to bend the screws 90 degrees at each of the marked points, both the 2-inch mark and the 3-inch mark. The screw should now form two separate "L" shapes, connected with the center 3-inch portion.
Screw the 2-inch portion of the step into a tree, ending with the 3-inch portion pointing downwards to the ground. This should leave a 7-inch portion of the screw perpendicular to the tree for you to step on as you climb up.