An f-hole cutter is used to cut the circular holes at the top and bottom of the f-holes.  This is the first step in cutting out the f-hole.  Commonly an f-hole cutter is used to prevent grain tear-out.  A pilot hole is drilled and the f-hole cutter is used to make the final cut, a bit from both sides.

My issue was that my f-hole cutter came in a bag.  After honing the cutters, I had nowhere to put them neatly, so they wouldn’t get damaged.  I solved this by building a small box.  The box is maple with paduke top and bottom, finished with tung nut oil.