A family-owned business from the start, the story of Prime begins in 1966. Louis "Leo" Grace Sr. started Grace Engineering in Memphis, Michigan. Over the years, the company grew and became known for developing innovative manufacturing practices and quality products. The Grace family's homestead in Memphis and the original building that housed Grace Engineering was once an old flour mill that had been built in the 1860's. A ledger was found on the premises that contained Thomas Edison's signature. Edison grew up in the nearby city of Port Huron, Michigan and would bring his family's wheat to the mill to be ground. Thomas Edison had a strong passion for innovation, and Grace Engineering and Prime have that same passion. In the 1980's, Louis (Lou) Grace Jr., Leo's son, took over Grace Engineering and further grew the business, focusing on precision manufacturing for demanding markets in the medical, hydraulic, and automotive industries, as well as credit card embossing.