Step 1: Materials
you will need
1 Set of scissor-like incredibly strong cutting device. (must be able to cut a penny)
Vice (semi-optional, you can probably get it to work without, but it makes life easier)
flat head screw driver
Step 2: Making the arrow head
use the hammer to flatten the penny as thin as possible without tearing the metal
besides making it sharper it work hardens the metal, making it stronger.
cut the penny into a sharp wedge shape, about 30 degrees.