The 1790 census shows George and John Foil in Mecklenburg Co. NC. After the county split in 1792 some records for Cabarrus Co. NC show Foil's but most appear to have changed their name to File. I am from Rowan Co. just northeast of there and there are lots of File's and Foil's in that county. It is my understanding that they are all related, at least in that part of the country. At least one post on the File Board shows the original name as Foile, changed to Feile and eventually to either File or Foil. Hope this helps.