I went to ArnFest last year. Its promoted as an Annual celebration of vintage machinery. There were ~30-40 sellers set up to sell there stuff on Saturday for the swap meet. Not all machinist related but enough for me to be happy. It took me less than an hour to see the whole swap meet. I sold some stuff and Mr. Pete was selling there next to me. I bought a chunk of aluminum from him. The swap meet was in Union, IL in the Illinois Railway Museum parking lot. This is a multiday event with lots of activities. You can google "ArnFest Illinois" and find their web site for further details. This years ArnFest is Sep 21-24.
No affiliation but a fun time if you like trains or vintage machinery.
John
Chipbreaker13