Had AtPro in truck and had only 20 mins. - found what appears to be a tie up for horses or used on old equipment - about 3 inches deep in and In over grown brush
I found one just like it a few days ago. I don't think it is for tying up horses. I have two horses.
At first I thought it might be some kind of cotter pin but I don't know until I clean it. I think the shaft part will, or is intended to rotate; i.e. it's not stable but I don't know for sure yet.
I wondered same. Just local church has rings similar that they would tie up horses to- they are mounted on foundation and few pillars. Heck a find just the same
Around here people still have them in their front yards, usually mounted on a granite post, along with big granite mounting blocks (for short people to get on horses from).