Harper had a shop on the northeast corner of Sixth and Cherry streets in Philadelphia. His original business was the manufacture of saws. His shop produced the Birch Pattern cents.
He may have produced the 1795 Jefferson cent patterns in an attempt to get a contract for coinage. He declined the position of assistant coiner of the mint. Harper worked with Albion Cox and Thomas Goadsby for the coinage of New Jersey coppers.
It is believed that the 1792 half dismes were produced at his shop.Source credit: Pete Smith, American Numismatic Biographies