"George E. Cawthon" wrote in message ...
todd wrote:

"Bob Gramza" wrote in
y.com:


"McQualude" wrote in message
...
: (Fred the Red Shirt) said:
:
: I found this question in another group (misc.rural)...
: Which is stronger, a round post or square post? Assume the
: posts are both made from the same wood and are both equivalent
: in width.

: Answering a different question, here but:

: If you start with a tree trunk which is typically what you start
: with for a fence post, it will be stronger if you leave it round
: than if you square it up.
:
: No, that is the question. I gave the same answer you gave, but not
: quite as clearly perhaps. I was hoping that someone would be able to
: support it, because I have no proof and I don't think math will
: answer this question.
: --

Of course math will answer the question although I suspect there is
some leg-pulling going on here. You want the fence post to be strong,
how, like so it doesn't fall over when a cow leans on the fence, right?

But you don't need math, you just need two brain cells to rub together.
If you start with a tree trunk that is round and square it then you
get a square post that is, at most, as wide accross the diagonals as
the diameter of the original tree. Now, suppose you want to reinforce
it. How would you do that? One way would be to nail extra boards to
all four sides of the post. OK, so take the four slabs you sawed off
to make it square and nail them back on.

The square beam might have a better strength to weight ratio but
who gives a damn? It's sitting in a hole in the ground, not on
your foot.

If you want to maximize the strength to weight ration then saw the
tree into lumber and construct box beams for your posts. Try sug-
gesting that over on misc.rural. Heck you can drill a little hole
in the side and they can double for birdhouses.

: McQualude

I would think that utilities would use square telephone poles if they
were stronger instead of leaving them round. They spend a lot of money
and resources on the poles they push into the ground.

Apparently, you've never tried to drill a square hole in the ground. ;-)

What, you never heard of a designated dirt mortiser?


From an engineering mechanics point of view, this is a very simple problem.
However, it probably breaks down for utilities on the basis of cost, i.e.,
it's just cheaper to get a round pole of similar strength than a square
pole. There are probably a hundred other reasons that make round poles
more workable (easier to climb with spikes, don't have to be oriented any
particular way, insulator bases are designed with round poles in mind, etc,
etc).

todd

I think it boils down to economy and simplicity. You have
to start with a much larger tree to get a square pole with
the same strength of a round pole. And, you don't need to
send it through a sawmill or buy larger trees. Simplicity
depends on the type of wood. In the west, lots of poles are
lodgepole pine which grows straight with a long length that
changes very little in width.

Yes, if you start with a larger tree why not just stick it in
the ground instead of spending money to square it and make it weaker?

OK, they want the poles to be reasonably uniform in cross section,
but seriously, if you start with an almost round pole (tree trunk)
then the strongest symetrical pole you can get which will also
involve removing the least wood, will be a pole with a circular
cross section tangent to the inside of the trunk.

--

FF