Step 1: Make the jig
Cut the wire and file it if necessary so that its end is reasonably flat.
Drill a hole in the wood into which the wire can fit snugly.
Bend the wire into a "U" shape and insert one end into the wood.
Tweak the bend in the wire so that the other end presses lightly against the wood and stays still.
Step 2: Use the jig!
Release the free end of the wire gently so that it holds your part against the board.