Ignoramus31268 wrote:
Our old mailbox was hit by cars, snowplows etc, too many times. It is
falling apart. (no foul play involved, just a lot of idiot drivers and
snowplow operators)

I made a swinging arm for a mailbox, so that when the mailbox is hit,
it swings away and then back.

So, now is the time for installing a new mailbox post. I bought a 30"
post support that is made to be beaten into the ground with a
sledgehammer. It is like an arrow with four fins.

I am now having second thoughts and am not sure if this is a good long
term solution. One of the reasons is that there is going to be quite a
bit of tipping moment due to a little longer swinging arm. (my guess
about 40-60 extra foot pounds of moment of force).

I want this mailbox to stay vertical and not "tip".

I live in Northern Illinois, so we have frequent freeze/unfreeze
cycles of soil.

So... What's a good way of mounting a mailbox post? Maybe I should set
that mailbox post support at least partially into concrete? (ie, digh
a shallow hole, beat it into the hole level with ground, and fill the
hole with concrete?

i

Do it like a corner post or gate post. Put two
posts in the ground about 3 feet apart and 3 feet
into the ground and tie the two posts together at
the top and the bottom with cross pieces. Posts
are at a right angle to the road of course.

Works everywhere I've been with much stronger
forces on the posts than a simple mailbox. If you
make the mailbox arm of 1-1/4" pipe and just stuff
that into an appropriate size pipe attached to the
post, you can readjust it anytime you want by
moving the larger pipe a bit on the post. Course
you really want the larger pipe angled toward the
road, so that the arm naturally swings toward the
road.