which coins did he work on in the mint?
1792 half disme
Introduction
 and was responsible for the designs of early American copper coinage, as well as the 1792 half disme which some authorities consider the first United States coin.
who was adam eckfeldt? John Adam Eckfeldt was a worker and official of the United States Mint. when did he start designing coins? 1793
He was responsible for the designs of early American copper coinage Cents and half cents. E.arly American copper coinage, as well as the 1792 half disme.
Adam Eckfeldt Adam Eckfeldt Adam Eckfeldt
Introduction Coin designer and Mint official Introduction
engraved some of its early dies, and was responsible for the designs of early American copper coinage, as well as the 1792 half disme which some authorities consider the first United States coin. He was appointed assistant coiner of the Mint in 1796, and became chief coiner on his predecessor's death in 1814.

Eckfeldt served a quarter century as chief coiner, during which time the Philadelp During Eckfeldt's childhood, the thirteen British colonies along the Atlantic coast of what is now the United States revolted, and so the United States of America secured its independence. After the United States Constitution was ratified, Congress and many government offices came to be housed in Philadelphia, including the newborn Mint of the United States. Adam Eckfeldt built the first screw press for the new facility in 1792, the same year that the Mint Act of 1792 was passed by Congress authorizing a mint, and cut the obverse die for the experimental Birch cent of that year. He also built other machinery for the Mint, and helped superintend the early coining.
In 1792, the Mint acquired three balances from Eckfeldt, who also lent the Mint his lathe (used for turning dies). Eckfeldt is believed to have made the die from which the 1792 half disme, considered by some the first official U.S. coin, was struck—in 1829, a visitor to the Mint met Eckfeldt and later described him as "an arti Adam Eckfeldt built early presses for the Mint, engraved some of its early dies, and was responsible for the designs of early American copper coinage, as well as the 1792 half disme which some authorities consider the first United States coin
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Adam Eckfeldt [SEP] Introduction
John Adam Eckfeldt (June 15, 1769 – February 6, 1852) was a worker and official in the early days of the United States Mint. A lifelong Philadelphian, Eckfeldt served as the second chief coiner of the Mint, from 1814 until 1839. Eckfeldt's father owned a large smithy and involved himself in early attempts at American coinage. Adam Eckfeldt built early presses for the Mint, engraved some of its early dies, and was responsible for the designs of early American copper coinage, as well as the 1792 half disme which some authorities consider the first United States coin. He was appointed assistant coiner of the Mint in 1796, and became chief coiner on his predecessor's death in 1814.