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


I put in one of those spike-type anchors on my mailbox and so far it has
worked out very well and is by far the easiest anchorage method I've
heard of. The cantilever on my mailbox arm is only about two feet but
the box itself is one of the welded heavy-gauge "bulletproof" sorts so
there is probably more tipping force than might be supposed at first
glance. My local soil is heavy and actual ground freeze is pretty much
unheard of so nature is doing less to pop it out than what you will
experience.

One idea that suddenly popped into mind that might be of assistance in
your situation is to have an angled support from the back (away from the
road) side of the post and going down to a deadman anchor. This would
take up the entire load of the cantilevered arm and convert it into a
downward force on the main post. This would help with the frost heave
situation and if the deadman is below the freeze line it shouldn't be
affected.

Have fun. I had several of my mailboxes eaten by snowplows when I lived
in Alaska and I know how frustrating it is to wake in the morning to
find the bits and pieces blown over the lawn by the city's blower.

--
John McGaw
[Knoxville, TN, USA]
http://johnmcgaw.com

I guess you could put a steel beam r such in level with the ground and
bolt a bendable or break away pole to the ground anchor.

at least this way when some jerk takes out the pole no futher digging
is necessary