Mint-made errors are called "type-2 blanks (or planchets)" after an upending mill adds uniform, rounded rims. Type-2 blanks may also be considered striking errors as they are prepared correctly, but are released without having been struck. A misfeed can occur when the metal strip is fed through the blanking machine. The punches sometimes overlap the leading edge of the metal producing a straight clip. Sometimes, the punches strike an area of the strip which overlaps the hole left by the previous strike producing a curved clip. Sometimes punches strike the irregular trailing edge of the metal strip producing irregular clips. Coins are
Sheet metal Sheet metal Sheet metal is metal formed by an industrial process into thin, flat pieces. Sheet metal is one of the fundamental forms used in metalworking and it can be cut and bent into a variety of shapes. Countless everyday objects are fabricated from sheet metal. Thicknesses can vary significantly; extremely thin sheets are considered foil or leaf, and pieces thicker than 6 mm (0.25 in) are considered plate steel or "structural steel." Sheet metal is available in flat pieces or coiled strips. The coils are formed by running a continuous sheet of metal through a roll slitter. In most