Definition: When freshly punched out of the coin metal strip, a coin preform is called a “blank”.  One side (the top side) is completely flat while the bottom side shows a subtle down warping along its perimeter.  This reflects the fact that the disc was forced through a hole in a perforated base plate by the force of the blanking die (punch).  The edge of a blank usually shows a “cut-and-tear” texture. As the blanking die penetrates the coin metal strip, it shears through the upper part of the strip, leaving the upper half of the edge relatively smooth.  The remainder of the blank tears away from its hole, leaving the lower portion of its edge with a roughened texture.

A blank eventually makes its way to the upset mill, where it is compressed between a rotating inner drum and a fixed half ring.  The upset millsqueezes the blank to a smaller diameter, whereupon it becomes a planchet.  Upsetting smooths the edge and produces a
low proto-rim on both faces. Occasionally a blank evades the upset mill or the sides of the upset mill fall out of adjustment, so that the blank is not rolled and squeezed.