1928-S Repunched Mintmark RPM-001

Description

Bearing the RPM-001 designation for the 1928-S Mercury dime, this variety shows an S/S West displacement — the initial S mintmark punch was placed too far east (to the right), and the corrective second punch landed to the west (left), leaving vestiges of the first impression visible as a partial secondary S extending beyond the right edge of the accepted final position. Adolph A. Weinman's celebrated winged-cap Liberty head design, widely nicknamed the "Mercury" dime despite depicting Liberty rather than the Roman god, places the S mintmark on the reverse adjacent to the fasces. San Francisco struck approximately 4.16 million Mercury dimes in 1928, a relatively low mintage that contributes to the date's scarcity in higher grades. The hand-punching process for adding mintmarks to working dies was inherently imprecise: a mint employee positioned a letter punch bearing the S over the appropriate location on the die, struck it with a hammer, and inspected the result. If the initial impression was unsatisfactory — too far east in this case — a corrective punch was applied at the intended position. Because the die steel retained the initial impression permanently, the first S could not be removed, resulting in the S/S overlap that defines a repunched mintmark. The westward direction of correction means collectors should look for secondary S traces to the right (east) of the final mintmark position, where the initial misplaced punch left its shadow. Under 10-15x magnification focused on the S mintmark area, the overlapping serifs and curves of the two S impressions become visible, with the displacement most apparent at the terminal points of the letter where the two punches diverge most.

External References