Right before I married my now wife her mailbox was mowed down by some local teenagers that smashed an entire block of mailboxes in her neighborhood. My father in law was much like me in that if something needed to be repaired or replaced it should be over engineered and be designed to last for a long time.
He went to a local friend that worked at an oilfield pipeline yard. They cut off a piece of heavy walled drilling pipe that was likely 10 inches in diameter. He has a power post hole digger he brought from the farm and he dug a deep hole, filled it with a lot of concrete and put a mailbox on top. Done.
They guy that lived across the street remained a friend. He said that just a few years ago in the middle of the night there was a loud THWANG! and by the time he got outside the driver had run off. A car was wrapped around the unbent mailbox pole. Of course the punk kid driver called it in as stolen. The other mailboxes on that side of the street were flat, but the punk's car met it's match with that mailbox.
