Home 
Search 
Today's Posts 

Woodworking (rec.woodworking) Discussion forum covering all aspects of working with wood. All levels of expertise are encouraged to particiapte. 
Reply 

LinkBack  Thread Tools  Display Modes 
#1




Wood Question: Which is stronger, a round post or square post?
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.  McQualude 
#2




Wood Question: Which is stronger, a round post or square post?
the square post. more wood!
"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.  McQualude 
#3




Wood Question: Which is stronger, a round post or square post?
Depends on the load, but I'm assuming you mean under deflection. If so, the
square post is stronger as it has a larger surface area associated to the top and bottom chords. This assumes all corners have been broken for stress concentration relief. If you mean a load under tension, it's strictly a matter of cross sectional area (assuming a consistent modulus of elasticity across the section) thus the square section again would win...as it would under compression. Rob  Remove CC for email and please visit our web site: http://www.robswoodworking.com "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.  McQualude 
#4




Wood Question: Which is stronger, a round post or square post?
"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.  McQualude As another poster indicated, assuming we're talking about bending, the moment of intertia of a square crosssection is L^4/12. For a circular crosssection, it's pi*D^4/64. I had to do the calculations three times to convince myself that this is correct, but all things being equal, a square post is 70% stronger than a round one when subjected to bending (this is assuming that the diameter of the round post is equal to the sides of the square crosssection). Keep in mind that the square has 27% more crosssection to start with, though. Perhaps a fairer comparison would be to compare equivalent crosssectional areas. If equal crosssectional areas are assumed, the square crosssection is about 5% stronger. todd 
#5




Wood Question: Which is stronger, a round post or square post?
If it is made of bois de arc, it doesn't matter. It won't break.
On Mon, 10 Nov 2003 21:25:28 0600, "todd" wrote: "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.  McQualude As another poster indicated, assuming we're talking about bending, the moment of intertia of a square crosssection is L^4/12. For a circular crosssection, it's pi*D^4/64. I had to do the calculations three times to convince myself that this is correct, but all things being equal, a square post is 70% stronger than a round one when subjected to bending (this is assuming that the diameter of the round post is equal to the sides of the square crosssection). Keep in mind that the square has 27% more crosssection to start with, though. Perhaps a fairer comparison would be to compare equivalent crosssectional areas. If equal crosssectional areas are assumed, the square crosssection is about 5% stronger. todd 
#6




Wood Question: Which is stronger, a round post or square post?
"Rob Stokes" wrote in message
s.com... Depends on the load, but I'm assuming you mean under deflection. If so, the square post is stronger as it has a larger surface area associated to the top and bottom chords. This assumes all corners have been broken for stress concentration relief. If you mean a load under tension, it's strictly a matter of cross sectional area (assuming a consistent modulus of elasticity across the section) thus the square section again would win...as it would under compression. Rob Have to be a little careful with compression of a post. A lot depends on the support conditions of the column, but you don't have to get a very slender column (i.e. long in relation to crosssection) before buckling becomes the primary failure mode. In this case, moment of intertia, not crosssectional area, will be the deciding factor. It still favors a square crosssection over a round one, just not as much as the crosssectional area alone would lead you to believe. todd (gotta use that materials engineering education for something these days). 
#7




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. well if you measure corner to corner and the round post is the same in that measurement it would be stronger. across the square post would be.  KnightToolworks & Custom Planes Custom made wooden planes at reasonable prices See http://www.knighttoolworks.com For prices and ordering instructions. 
#8




Wood Question: Which is stronger, a round post or square post?
McQualude writes: 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. Under what conditions? Compression loading as in a column? The bending loading on a post at ground level that is buried a couple of feet in the ground? You have to define the problem first. HTH  Lew S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland) Visit: http://home.earthlink.net/~lewhodgett for Pictures 
#9




Wood Question: Which is stronger, a round post or square post?
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 
#10




Wood Question: Which is stronger, a round post or square post?
McQualude writes:
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. What dou you mean by "equivalent" in width? Same diameter as length of side of the square? Then the square is stronger, because the additional material in the corners adds considerably to the geometrical moment of inertia. If "equivalent" is meant that the same strength is reached there is no difference...  Dr. Juergen Hannappel http://lisa2.physik.unibonn.de/~hannappe Phone: +49 228 73 2447 FAX ... 7869 Physikalisches Institut der Uni Bonn Nussallee 12, D53115 Bonn, Germany CERN: Phone: +412276 76461 Fax: ..77930 Bat. 892RA13 CH1211 Geneve 23 
Reply 
Thread Tools  Search this Thread 
Display Modes  


Similar Threads  
Thread  Forum  
Footings crossing boundary  UK diy  
Further to my last post entitled 'Flushing and treating central heating question'  UK diy 