Finning occurs when part of the coin's circumference extends beyond the intended rim. The fin is usually not filled, but the finned part of the coin can be filled in on the opposite side. There are degrees of finning, filled, partially filled, and hanging. The hanging fin does have some added value, but most other finning is of no added value. The first photo (1987 Lincoln cent) shows a rim finned but filled on the opposite side of the coin. The second photo shows a deep impression around 1/2 of the coin's circumference.
By: Stan McDonald author and numismatist