It is pretty plain but is a big honking piece of metal and has a B in it. The people that built the house had the last name of Berkshire. Thank you for looking and I hope we can solve it. I looked at all the photos listed for American hallmarks and I thought I was going to surely find it under the R's. Sadly no. It looked close to one that made some shakers and hammered bowls but just not the same. Enjoy the photos!