Mint-made errors 5 centavos. Foreign coins struck on a U.S coin planchet or vice versa are very uncommon and hold a high value. Authentic error coins should not be confused with coins that are damaged after being minted, which is known as post-mint damage (PMD) or post-strike damage (PSD). Mints purchase long strips of metal which are fed through blanking machines that punch out disks known as blank planchets (or simply as planchets or blanks) on which coins are struck. This determines the size and shape of eventual coins. The punched disks are first known as "type-1 blanks (or planchets)". The disks
Walking Liberty half dollar lowering the relief slightly, adjusting the force with which the Mint's presses struck the planchets or blanks, and better preparing the planchets for striking. Joyce's position prevailed, and Barber and his department prepared working dies for striking of circulation pieces, omitting Barber's beaded border and wide space between rim and design. Working dies were at the Denver and San Francisco Mints on , and production began at all three mints soon after. In late December Weinman, who had received no update from the Mint since being told of the Barber modifications, but who had read in the newspapers that the