My old mailbox post was in rough shape, so I decided to build a new one. I used a treated 4x4x12 that cost less than $20. I dressed mine up with a copper pyramid post cap for a few dollars more, but it isn't necessary.
Dimensions are as follows:
Height of post above ground= 70" (not counting the buried part of post) but check postal regulations for official height needed.
Cross bar length= 31" overall, 18" protruding from front of post & 9.5" from rear.
Knee brace length= 11" at the longest point of the miters.
Crossbar set 20" down from top of post to top of crossbar.
Filmed on my iPhone X using my homemade iPhone camera stand. Logo design by Brandon Kettle. Video music is "James River" by DJ Williams.