Anticipated technical challenges associated with producing commemorative coins with a concave obverse and convex reverse led U.S. Mint officials to begin research and development for the 2014 National Baseball Hall of Fame coins long before final designs were approved.

Because designs had not been selected, early testing required the use of what are called "nonsense dies," which bear designs that are in semblance of coin designs but do not duplicate any actual coin designs. For the Baseball coin program, the Mint selected nonsense designs with a sports theme.

Nonsense designs, "featuring an 8-ball reverse and pool shooter obverse, were traditionally sculpted, 3D scanned and then digitally recreated to start the process," said Steve Antonucci, branch manager for Digital Development, Research & Development for the U.S. Mint at Philadelphia. "These designs were intended to simulate dome configurations and height of relief details that might be encountered when the baseball designs were finally approved and sculpted."

Antonucci said the designs were then machined on computerized numerically controlled milling equipment "directly into die form to speed up the coinability and die testing phases."

The creation of the nonsense dies represents the first time, according to Antonucci, that the U.S. Mint has CNC-milled original dies for such a purpose.

"The efforts we've undertaken to produce these coins reflect the passion, pride and professionalism that the men and women of the Mint have for their work," said Tom Jurkowsky, director of corporate communications for the U.S. Mint. "What we've done to prepare to mint the baseball coins may be viewed as being extraordinary. But it's really demonstrative of how we approach all of our products with only the strongest possible commitment to quality and excellence."

In an Oct. 18 telephone interview, Antonucci said the nonsense dies, which he prefers to refer to as "research dies," bear a pool player on the concave obverse. The convex reverse on the research die depicts an 8-ball billiard ball. Stitching was placed around the circle of the 8-ball design on the research die reverse to simulate a baseball and provide Mint technicians information on die stress issues.

When the common obverse and reverse designs were selected for the coins, testing could continue using those designs.

The adopted common obverse, approved Sept. 9 and announced Oct. 15 for the gold $5 half eagle, silver dollar and copper-nickel clad half dollar, bears a baseball glove design.

The design was created by San Luis Obispo, Calif., artist Cassie McFarland, who will received $5,000 for winning the open design competition from which her design was selected.

The adopted common reverse, bearing a mandated rendition of a baseball similar to that used by Major League Baseball, is the work of U.S. Mint Sculptor-Engraver Donald Everhart II.

Everhart sculptured both obverse and reverse designs.

To read the complete article, see:Baseball coins prove technical challenge for U.S. Mint staff(www.coinworld.com/articles/baseball-coins-prove-technical-challenge-for)