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  #41   Report Post  
McQualude
 
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Default Wood Question: Which is stronger, a round post or square post?

"Michael Daly" said:

We still haven't seen a decent definition of what "equivalent
width" means, only a vague statement.


Yes, I answered this question - meaning that the width of the wood
makes no difference.
--
McQualude
  #43   Report Post  
David Binkowski
 
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Default Wood Question: Which is stronger, a round post or square post?

Too bad you didn't just say the same circumference. You would
have avoided all the "what do you mean by same size" questions.

If THAT were the question I'd say round has a slight advantage,
not in terms of taking a blow that breaks it in two, but the lack
of square corners begging to be dented and splintered makes
the entire structure more "sound". If you took the same amount
of material and shaped it with alot of delicate edges and thin
areas, the structure is weaker due to its shape, and the many
vulnerable points.

But if you're just wanting to know which shape would snap
under a destructive load test, you'll have to ask an engineer.


--
The software said it ran under Windows 98/NT/2000, or better.
So I installed it on Linux...
"Fred the Red Shirt" wrote in message
om...
McQualude wrote in message

...
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.

--

FF



  #44   Report Post  
Michael Daly
 
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Default Wood Question: Which is stronger, a round post or square post?

On 12-Nov-2003, McQualude wrote:

"Michael Daly" said:

We still haven't seen a decent definition of what "equivalent
width" means, only a vague statement.


Yes, I answered this question - meaning that the width of the wood
makes no difference.



If the width makes no difference, then you're comparing apples and
oranges. A round post 12" in diameter will be stronger than a
square one 1" on a side. OTOH, a square 12" on a side will be
stronger than a round one 1" in diameter.

Bets are off it you're comparing balsa to white oak with arbitrary
dimensions.

Mike
  #45   Report Post  
larry
 
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Default Wood Question: Which is stronger, a round post or square post?

todd wrote in message . 1...
(larry) wrote in
om:

McQualude wrote in message
...
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.


Don't listen to all these engineers. Wood should be used based on its
properties, not their theories. Moment of inertia? If they ever
touched a real piece of wood I would be surprised.


Well, I guess you should be surprised. You must be one of those folks who
doesn't let a little thing like physics get in the way of what you think is
right. Maybe you want to enlighten us on how wood resists bending in a
different way conceptually than other materials. Until then, crawl back
into your hole and leave the heavy lifting to someone who has both the
theoretical and practical experience. No material is going to match the
formulas exactly. Wood complicates matters further because it is
anisotropic (that means it has different physical properties in different
directions). However, the formulas (these aren't just theories, by the
way, much less *my* theories) will still give good guidance in answering a
question such as the one posted originally.

todd


Sorry Todd. I'm new to this posting thing(no pun intended). I had sent
a reply before the short one that did have some content. I must have
deleted rather than sent it. My point was basically that we are
talking about fence posts. On wood of that scale used for that
purpose, the limiting factor for strength would be grain runout. I
assumed that anything "round or square" would be from a mill. The
sawing process cuts across grain lines leaving weak spots. Using any
shape of split timber would be preferable. When splitting posts I
generally don't take the time to round them off or square them up. So,
if the question was which shape, round or square, should I buy from
home depot the answer is it doesn't really matter. It will take me a
while to recognize the difference between a woodworking question and
one that is thrown out there to noodle out. By the way, I know a
couple of engineers that are woodworkers as well. They would be the
first to admit that they take the material properties thing a little
too far. I'm used to ribbing them for it. Out of context that short
message did deserve that answers it got.

Larry


  #46   Report Post  
McQualude
 
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Default Wood Question: Which is stronger, a round post or square post?

todd said:

folks who doesn't let a little thing like physics get in the way
of what you think is right.


I'm listening, explain why a round or square wooden fence post is
stronger if the width of the post is not a factor.

I, and one or two others, postulated that the round post would be
stronger because it maintains the integrity of the tree (assuming the
post started as a whole tree). No engineers have responded to rebut
any of those comments.
--
McQualude
  #47   Report Post  
todd
 
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Default Wood Question: Which is stronger, a round post or square post?

McQualude wrote in news:Xns9432E7CBE3C78mcqualude@
24.25.9.43:

todd said:

folks who doesn't let a little thing like physics get in the way
of what you think is right.


I'm listening, explain why a round or square wooden fence post is
stronger if the width of the post is not a factor.

I, and one or two others, postulated that the round post would be
stronger because it maintains the integrity of the tree (assuming the
post started as a whole tree). No engineers have responded to rebut
any of those comments.


Since you're assuming that the round post has the center of the tree as
it's center, I'll assume that the square post is the same. Therefore, the
square post contains all of the material of the round post, plus the
material in the square corners. Unless you can explain how added material
in the corners weakens the post, consider your postulate rebutted.

Note I haven't spent much time talking about whether a square post is an
efficient means of making a post (though I did touch on this point a couple
of posts ago). You could probably make an argument of why the hell are we
talking about this anyway. How much load is a fence post likely to see in
the first place? I answered a general question with a general answer. We
would have to have a *lot* more information to arrive an an in-depth
answer. A notable example would be what would the failure mode of a wooden
post in bending be? It could fail in tension (at the top of the post
(opposite side to the direction of load), in compression at the bottom of
the post, or in shear in the center. You could make a case for being
concerned about the shear strength of a post with the center of the tree
(not an area known for high strength) being located at the area of highest
shear stress. Unless you're prepared to enter into such a discussion, I'd
leave the postulating alone.

todd
  #48   Report Post  
larry
 
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Default Wood Question: Which is stronger, a round post or square post?

McQualude wrote in message ...
todd said:

folks who doesn't let a little thing like physics get in the way
of what you think is right.


I'm listening, explain why a round or square wooden fence post is
stronger if the width of the post is not a factor.

I, and one or two others, postulated that the round post would be
stronger because it maintains the integrity of the tree (assuming the
post started as a whole tree). No engineers have responded to rebut
any of those comments.


The integrity of the tree you are tying to maintain in this situation
is the grain that runs from end to end in the tree. A tree trunk the
size of a post would have all of the grain intact. A tree four times
the size of the post split into four pieces would have the same
unbroken grain end to end, like a handfull of straws. The cross
section of the post is a secondary. So if you have two pieces of wood
from the same tree with no grain runout,one round and one square in
section and you assume that being the same size refers to cross
sectional area, I would think they would be the same strength. From
this point someone with a better knowledge of physics would have to
take over. I just know wood.
  #49   Report Post  
P van Rijckevorsel
 
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Default Wood Question: Which is stronger, a round post or square post?

todd schreef
Since you're assuming that the round post has the center of the tree as
it's center, I'll assume that the square post is the same.


+ + +
From a practical point of view this assumption is not realistic.
A round post is likely to be 'whole tree'
A square post is likely to be sawn from a bigger trunk.

This means that a round post consists partly of juvenile wood, a weakening
factor. A square post will consist of mature wood.
Ergo: the strength of the material will not be equal in these two cases. It
will be less in a round post
PvR





  #50   Report Post  
Al Reid
 
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Default Wood Question: Which is stronger, a round post or square post?

Ah, but your assumption is that the square post has been cut from the center of the tree and contains
only heartwood. How do you know it wasn't cut from a section of the tree sear the growth rings and
thus contains both sapwood and heartwood?

--
Al Reid

"It ain't what you don't know that gets you into trouble. It's what you know
for sure that just ain't so." --- Mark Twain

"P van Rijckevorsel" wrote in message ...
todd schreef
Since you're assuming that the round post has the center of the tree as
it's center, I'll assume that the square post is the same.


+ + +
From a practical point of view this assumption is not realistic.
A round post is likely to be 'whole tree'
A square post is likely to be sawn from a bigger trunk.

This means that a round post consists partly of juvenile wood, a weakening
factor. A square post will consist of mature wood.
Ergo: the strength of the material will not be equal in these two cases. It
will be less in a round post
PvR









  #51   Report Post  
Mark
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?



todd wrote:


Since you're assuming that the round post has the center of the tree as
it's center, I'll assume that the square post is the same. Therefore, the
square post contains all of the material of the round post, plus the
material in the square corners. Unless you can explain how added material
in the corners weakens the post, consider your postulate rebutted.




Because where the grain exits/ enters the post it creates uneven stress.



You could probably make an argument of why the hell are we
talking about this anyway.



Mental masturbation.



--

Mark

N.E. Ohio


Never argue with a fool, a bystander can't tell you apart. (S. Clemens,
A.K.A. Mark Twain)

When in doubt hit the throttle. It may not help but it sure ends the
suspense. (Gaz, r.moto)

  #52   Report Post  
todd
 
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Default Wood Question: Which is stronger, a round post or square post?

"P van Rijckevorsel" wrote in
:

todd schreef
Since you're assuming that the round post has the center of the tree
as it's center, I'll assume that the square post is the same.


+ + +
From a practical point of view this assumption is not realistic.
A round post is likely to be 'whole tree'
A square post is likely to be sawn from a bigger trunk.

This means that a round post consists partly of juvenile wood, a
weakening factor. A square post will consist of mature wood.
Ergo: the strength of the material will not be equal in these two
cases. It will be less in a round post
PvR


I'm telling that from a practical point of view, you don't have the first
clue how the post will fail. (For the record, I've already stated that I
don't know what the compression strength, tensile strength, and shear
strength is for various woods, although I'm sure I could google it if I was
so inclined). Your assumption regarding the strength of juvenile only
matters if shear is the primary failure mode. If the primary failure mode
is tension or compression, then it doesn't really matter what's happening
in the center.

todd
  #53   Report Post  
todd
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?


"Mark" wrote in message
...


todd wrote:


Since you're assuming that the round post has the center of the tree as
it's center, I'll assume that the square post is the same. Therefore,

the
square post contains all of the material of the round post, plus the
material in the square corners. Unless you can explain how added

material
in the corners weakens the post, consider your postulate rebutted.




Because where the grain exits/ enters the post it creates uneven stress.


I suppose that sounds good, but I don't think in practice it's really going
to have a very large effect at all, if any. In the worst case, if we
assumed that the shear strength between growth rings was very low, you might
be able to argue that it really wouldn't help, but I don't see how it would
hurt. This isn't like machining a notch into the additional area that would
create a stress concentration, which could actually produce an overall
weaker member (heh, heh....he said "member").

todd


  #54   Report Post  
Charles Krug
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?

On Fri, 14 Nov 2003 09:17:34 -0600, todd wrote:

This means that a round post consists partly of juvenile wood, a
weakening factor. A square post will consist of mature wood.
Ergo: the strength of the material will not be equal in these two
cases. It will be less in a round post
PvR


I'm telling that from a practical point of view, you don't have the first
clue how the post will fail. (For the record, I've already stated that I
don't know what the compression strength, tensile strength, and shear
strength is for various woods, although I'm sure I could google it if I was
so inclined). Your assumption regarding the strength of juvenile only
matters if shear is the primary failure mode. If the primary failure mode
is tension or compression, then it doesn't really matter what's happening
in the center.


For posts made of a suitable wood in suitable size, the "usual" failure
is that it rots at the ground line.

If your post fails before it rots, it was too small.

Usually, you string the wire on the inside of the line posts, so that an
animal pushing against it doesn't pull the staples, and around the
corner posts.

There are as many ways to brace corners as there are fence builders. My
preferred method was to have the line posts at 16', except at the
corners, where I'd have the first line post 8' away with a horizontal
member in compression, and a wire tensioner making SURE it STAYS in
compression. This was woven wire for sheep, which carries a good bit
more total tension than barbed wire for cows. Dairy farmers got away
with smaller corner posts and less substantial bracing, but they needed
twice as many line posts.

Had a neighbor who had sheep AND a commercial cabinet shop. His fences
were made from "scraps." It didn't hold sheep in (more importantly dogs
out) any better than our fence did, but DAMN did it look nice.

  #55   Report Post  
P van Rijckevorsel
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?

Al Reid schreef
Ah, but your assumption is that the square post has been cut from the

center of the tree and contains only heartwood.

+ + +
Just the reverse. If a tree is sawn up into square posts only one of these
will have 'heartwood'. In a perfect world this would be thrown out and not
used as a pole.
PvR






  #56   Report Post  
P van Rijckevorsel
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?

todd schreef in
If the primary failure mode
is tension or compression, then it doesn't really matter what's happening
in the center.


+ + +
That is a good point, but still assumes posts of sufficient diameter that
this outer part is free of juvenile wood.
PvR


  #57   Report Post  
Lawrence Wasserman
 
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Default Wood Question: Which is stronger, a round post or square post?

Is this post for a fence or a ... MAILBOX?


--

Larry Wasserman Baltimore, Maryland


  #58   Report Post  
A Dog Named Stain
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?


"Lawrence Wasserman" wrote in message
...
Is this post for a fence or a ... MAILBOX?


--


DUH, everyone knows you use steel, concrete and brick for a mailbox.
That way any mail box bashers get their arms broken or better yet, die
in a fiery crash.

Please pass the popcorn.


  #59   Report Post  
McQualude
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?

todd said:

folks who doesn't let a little thing like physics get in the
way of what you think is right.


I'm listening, explain why a round or square wooden fence post
is stronger if the width of the post is not a factor.

I, and one or two others, postulated that the round post would
be stronger because it maintains the integrity of the tree
(assuming the post started as a whole tree). No engineers have
responded to rebut any of those comments.


Since you're assuming that the round post has the center of the
tree as it's center, I'll assume that the square post is the
same. Therefore, the square post contains all of the material
of the round post, plus the material in the square corners.
Unless you can explain how added material in the corners weakens
the post, consider your postulate rebutted.


You still made the same assumption that the square post contains more
wood, even after I've told you twice that isn't true.
--
McQualude
  #60   Report Post  
todd
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?


"McQualude" wrote in message
...
todd said:

folks who doesn't let a little thing like physics get in the
way of what you think is right.

I'm listening, explain why a round or square wooden fence post
is stronger if the width of the post is not a factor.

I, and one or two others, postulated that the round post would
be stronger because it maintains the integrity of the tree
(assuming the post started as a whole tree). No engineers have
responded to rebut any of those comments.


Since you're assuming that the round post has the center of the
tree as it's center, I'll assume that the square post is the
same. Therefore, the square post contains all of the material
of the round post, plus the material in the square corners.
Unless you can explain how added material in the corners weakens
the post, consider your postulate rebutted.


You still made the same assumption that the square post contains more
wood, even after I've told you twice that isn't true.
--
McQualude


So far, the sum total of your information from what I see looking back in
the thread regarding the dimensions of the post has included the following
"both equivalent in width" and "the width of the wood makes no difference".
Personally, I don't have the faintest idea what the hell you mean by either
of those. I've defined the assumptions I've made pretty clearly. If you'd
care to be specific, I'd tailor my comments to your specific case.

todd




  #61   Report Post  
Michael Daly
 
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Default Wood Question: Which is stronger, a round post or square post?

On 14-Nov-2003, "todd" wrote:

If you'd
care to be specific, I'd tailor my comments to your specific case.


I think we should treat him as a troll. I've already asked him to
clarify the width issue and all he does is blather some more. It
would be trivial to clarify, but he just wants to be a PITA.

Mike
  #62   Report Post  
Jon Dough
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?

On Fri, 14 Nov 2003 23:34:46 +0000, McQualude wrote:

todd said:

folks who doesn't let a little thing like physics get in the way of
what you think is right.


Since you're assuming that the round post has the center of the tree as
it's center, I'll assume that the square post is the same. Therefore,
the square post contains all of the material of the round post, plus the
material in the square corners. Unless you can explain how added
material in the corners weakens the post, consider your postulate
rebutted.


You still made the same assumption that the square post contains more
wood, even after I've told you twice that isn't true.


Some people just can't see the forest for the trees...
A 4" square post would be stronger than a 4" round post. The square post
would be almost the equivilent of nailing a 2"x4" board of the same
material to the round post.
The only case I know of where a round post was stronger than a square post
is the corner post my Father set when I was a teenager. It was about 8"
diameter and about 9' long, fresh cut from a hedge tree and set in the
spring of the year. Being fresh cut, it took root and grew, now is about
a 16" diameter tree over 25 feet tall. It is still round though. It
never did grow square.

  #63   Report Post  
McQualude
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?

"todd" said:

So far, the sum total of your information from what I see
looking back in the thread regarding the dimensions of the post
has included the following "both equivalent in width" and "the
width of the wood makes no difference".


The question has already been answered, thanks anyway.
--
McQualude
  #64   Report Post  
McQualude
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?

"Jon Dough" said:

You still made the same assumption that the square post
contains more wood, even after I've told you twice that isn't
true.


Some people just can't see the forest for the trees...
A 4" square post would be stronger than a 4" round post.


Yes, that would be true, but that wasn't the question. Thanks, but
the question has already been answered.
--
McQualude
  #65   Report Post  
McQualude
 
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Default Wood Question: Which is stronger, a round post or square post?

"Michael Daly" said:

I think we should treat him as a troll. I've already asked him to
clarify the width issue and all he does is blather some more. It
would be trivial to clarify, but he just wants to be a PITA.


It was a simple question that several people already posted good
answers for. As I stated in the first post, I lifted the question
from another group because I thought a bunch of woodworkers might
have good answers, I gave you all the information that was available
in the original post. The original poster did not answer any
questions that were in the original thread, so I gave you all the
information that I had. I'm not sure how this makes me a troll, but
you can go **** yourself.
--
McQualude


  #66   Report Post  
Tom Watson
 
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Default Wood Question: Which is stronger, a round post or square post?

On Tue, 11 Nov 2003 02:44:43 GMT, McQualude
wrote:

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.



Wow, what a huge thread !



There's no way I'm wading through all the replies, as dinner is
waiting and I've got to fly.

If the "post" is a fence post and loaded on side

I was taught that the grain line-up, that would decide

As to whether or not it would resist the cow

(Our fence posts were square, and not round but it's "how"

the grain was a'running and not 'bout it's section

t'would resist our big bull with a full-blow erection

and, if our bull wanted to get out, when hot

a square or a circle, it didn't mean snot)

But, if you are saying a post is a column

And holds up big buildings and things that are solemn

Like kitchens and children and Grandfather's rocker

I'll spin you a truth that's not much of a shocker

A square that is six inch on each of it's sides

Has an area greater than circles that wide

The area's key, it's the thing that must rule

And he who says dif'rent is not but a fool.


Regards, Tom
Thomas J. Watson-Cabinetmaker
Gulph Mills, Pennsylvania
http://users.snip.net/~tjwatson
  #67   Report Post  
todd
 
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Default Wood Question: Which is stronger, a round post or square post?

"McQualude" wrote in message
...
"todd" said:

So far, the sum total of your information from what I see
looking back in the thread regarding the dimensions of the post
has included the following "both equivalent in width" and "the
width of the wood makes no difference".


The question has already been answered, thanks anyway.
--
McQualude


No ****. I've answered the thing about 5 times by now just by myself, not
including the other answers. Of course, I don't know how one could give an
accurate answer because based on the limited amount of information
available, there's no way to be specific. I included the assumptions that I
made in my examples.

todd


  #68   Report Post  
Michael Daly
 
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Default Wood Question: Which is stronger, a round post or square post?

On 15-Nov-2003, McQualude wrote:

so I gave you all the
information that I had. I'm not sure how this makes me a troll, but
you can go **** yourself.



What a lovely sentiment.

Why didn't you just answer "I don't have a clue, I just copied the question"
instead of giving ambiguous and vague answers about width. "Width doesn't
matter" is an irrelevant comment.

Mike
  #69   Report Post  
Mark
 
Posts: n/a
Default Wood Question: Which is stronger, a round post or square post?



Michael Daly wrote:


"Width doesn't matter" is an irrelevant comment.



That's what women tell us to make us feel better.


--

Mark

N.E. Ohio


Never argue with a fool, a bystander can't tell you apart. (S. Clemens,
A.K.A. Mark Twain)

When in doubt hit the throttle. It may not help but it sure ends the
suspense. (Gaz, r.moto)

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