Fullers

Fullers and other hardy tools for metal forming and necking.

**Since hardy holes are traditionally not exact some fine tuning of the tool maybe required**

Fairly good description from Wikipedia below:

In metalworking, a fuller is a tool used to form metal when hot. The fuller has a rounded, either cylindrical or parabolic, nose, and may either have a handle (an "top fuller") or a shank (a "bottom fuller"). The shank of the lower fuller allows the fuller to be inserted into the hardy hole of the anvil.

The fuller is a forging tool, used to spread the metal. The fuller is placed against the metal stock, and then either the top fulleror the stock is struck with a hammer. The rounded nose of the fuller spreads the metal more efficiently than the flat face of the hammer. "Fullering," more generally, refers to any forging process creating a sharp transition in cross-dimensional area; with care, some types of fullering can be achieved using only hammer and the edge of the anvil (which acts as the fuller).