Swing beams, also known as “bull beams”, are large-depth beams of which there is usually only one in an English-framed barn in a middle bent and extending from wall post to wall post. They came into use in the mid 1800’s to allow a clear span in the middle of the barn with no vertical center posts in the middle of the threshing floor. They were also tapered on the ends, with the bottom edge straight and the top edge bellied up. We have found swing beams as wide as 38” in the belly. Forming such a clear span in the middle of the barn allowed for a farmer to tether an ox in the center of the barn and walk him in a circle threshing out grain, thereby eliminating the need for flailing grain to free the grain kernels from the heads.