The United States Mint has been faced with a number of technological challenges over the past more than two decades putting edge letteringon United States coins.

Most U.S. coins today are produced with a plain edge or reeded edge.

In 1992, the Denver Mint struck the Uncirculated Olympic Baseball dollar first with a reeded edge. Then using a 20th century version of aCastaing-type machine like that used during the 18th and 19th centuries to deter counterfeiting, incuse edge lettering was imparted over the reedededge without crushing the reed details.

In 2007, first with the Presidential dollars, and two years later with the Native American dollars, Mint technicians were tasked with having toproduce the means to execute edge lettering.

The first year's production of Presidential dollars became a learning curve, since the edge inscriptions weren't applied during production ofcirculation strikes, but after, on equipment separate from the coinage presses.

The process was flawed, as thousands of coins escaped application of the edge devices or passed through the final step more than once, creatingoodles of error coins for collectors to locate.

It wasn't until 2008 that the final step was integrated into the end of the production line with the coinage presses.

To watch the complete video, see:
U.S. Mint tackles challenges of edge lettering: Monday MorningBrief, Oct. 3 (www.coinworld.com/videos/2016/10/monday-morning-brief-oct-3-2016.html)