For a 3 blade I use a 10 inch mill file and a piece of leather. That's it. I put the heads on a shaft, lay the file flat on 2 blades, sort of diagonally. Push the file away from you, back to tip. Start out with moderate pressure and get a lighter touch as you go along. Finish with just the weight of the file. Then, put the leather on a tabletop, piece of glass, tile ,ect. pull the broadhead towards you, back to tip. Just a few light strokes to remove the burr. If done right, they will CUT!! Good luck.