I think the general criteria is "3 full readable letters on the shield" for F. It appears that your coin meets that criteria. The eagle's feathers on the reverse also seem to be F quality. I'm far more concerned about the color of your coin - it is far too pale white for a coin of that age and wear. It should be a dark grey. Now, that may be the pictures. But, there's a strong chance this coin has been cleaned. I don't see hairlines in these pictures, but that color is just not right.
That's actually not a rim ding. It's a lighter place on the coin that the light reflected off of. You can see if you zoom that the rim maintains a normal curve.
Photograde calls for full but weak Liberty for fine. I ordered a copy of the Art and Science of grading just now. Thanks for the recommendation.
