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question about smaller beams

Started by SDM, April 29, 2015, 10:53:54 AM

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SDM

Hello,
  I was hoping to get some info about 6x6x20 posts. Can I make this size beam and not worry about centering the hart? I know with lager beams the hart should be centered to prevent movement. Thanks in advance.
           Shawn

sealark37

If you leave any heart material near the edge of your beams, it will cause a 20 footer to have some bowing.  Even with the heart perfectly centered, you may still have some bow.  I assume that you are cutting these beams for a pole building.  Some bow is acceptable.  The builder is usually careful to orient the bow where it causes the least problem.  Regards, Clark

Magicman

Nothing is always simple.  You can center the heart/pith perfectly and still get bowing.  Much depends upon what the tree was doing before it was felled.  Was it leaning, did it have more limbs on one side because of crowding or maybe for being an edge tree, etc.  And then when you eliminate all of the reasons for bowing, it bows anyway just because it can.   :-\
Knothole Sawmill, LLC     '98 Wood-Mizer LT40SuperHydraulic   WM Million BF Club Member   WM Pro Sawyer Network

It's Weird being the Same Age as Old People

Never allow your "need" to make money to exceed your "desire" to provide quality service.....The Magicman

longtime lurker

Pith timber in most species is significantly weaker then the surrounding true wood, and also more prone to shakes. Boxing the heart takes the pith and surrounds it with a thickness of stronger true wood.
From a strength perspective the smaller your boxed heart beam gets the more important it is to have the pith centered, so that there is a good "wrapper"  of true wood around the weak core portion.

Only after that should we consider straightness and as MM says... it'll do what it wants to do regardless.
The quickest way to make a million dollars with a sawmill is to start with two million.

drobertson

It's a gamble either way, but odds are better as near heart centered as possible for straightness.  I've found free of heart will bow, the percentages will vary but pretty certain a bow will occur, more so than heart centering.  It takes lots of flipping for the timber I saw, and as said,  no guarantee in the end,  got bit today with a SOG swoop with a 5x6, and have never seen this before. 
Should be in tolerance but not that pretty to look at in the rest of the stack.  At least the critical side was to the numbers. the other almost 1/4" dip, about a foot from the end for about a foot, then back straight again,  it was a pitchy pine, so, every log really has it's own behavior I have found.
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

fishfighter

Quote from: Magicman on April 29, 2015, 01:16:20 PM
Nothing is always simple.  You can center the heart/pith perfectly and still get bowing.  Much depends upon what the tree was doing before it was felled.  Was it leaning, did it have more limbs on one side because of crowding or maybe for being an edge tree, etc.  And then when you eliminate all of the reasons for bowing, it bows anyway just because it can.   :-\

This. I picked out the best trees to cut beams. Out of about 20, After I mortise some cuts, that sucker went to bowing big time. The pith was dead center from one end to the other.

customsawyer

What are you doing with the post?
Two LT70s, Nyle L200 kiln, 4 head Pinheiro planer, 30" double surface Cantek planer, Lucas dedicated slabber, Slabmizer, and enough rolling stock and chainsaws to keep it all running.
www.thecustomsawyer.com

Brad_bb

If you had the time or foresight, you could cut oversize, wait a few or more years stacked to allow drying, then recut to remove bow.  I don't know how long you'd have to wait for them to be stable enough.  From recent experience I know 120 years drying worked  ;D.  I recut and planed beams down to 8x8's that stayed dead straight.
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

fishfighter

I'm throwing up a a cabin green. ;D

Jim_Rogers

Lumber grading rules usually state that any timber over 5" x 5" should be boxed heart/pith centered both ends for strength.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

beenthere

Jim
Is that a grading rule that is published that you can link as a resource? tks
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

GeneWengert-WoodDoc

The first 15 or so years of growth of a stem consist of wood that is more flexible than wood created years later and further from the pith or heart center.  Along with this is, from time to time, in fact most of the time with softwoods like pine, the cells spiral around the tree instead of being perfectly vertical.  This causes twist.  As the spiral usually reverses after 15 or so years, there is less tendency to twist when the growth rate is slow so you have both 0 to 15 and a lot over 15 years also.  Plantation growth is often fast, so it is common to see twist in plantation material.  Twist causes a big issue with log cabins, obviously, as the twist shows up whenever the moisture changes.

Min addition, hardwoods form tensionwood and softwoods form compression wood, especially in the first 15 years.  Often, such wood, which shrinks lengthwise compared to no shrinkage in wood away from the pith.  Often such wood is concentrated in one region of a ring and so we have one section of the log that is shrinking lengthwise, while the rest of the wood is shrinking much less or none in the lengthwise direction.  When we get regions of lengthwise shrinkage, we will get bow no matter how we dry or how we stack, etc.

Ok?
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Jim_Rogers

Quote from: beenthere on May 01, 2015, 03:15:46 PM
Jim
Is that a grading rule that is published that you can link as a resource? tks

The book would be the NDS or national design specifications. and I don't believe you can access it online. I had to buy mine, based on that I don't think you can access it.

Another rule book would be NeLMA's grade rule book Section #6 for timbers 5" in thickness or larger.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

beenthere

Thanks Jim
If you run across it, please quote it as I'd like to see how it is stated.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

SDM

    Thanks to all. Unfortunately the customer needed them pressure treated so it didn't happen. But I am now armed with more knowledge. I do know if you put the pole barn up green the twisting and moving tightens the structure. Sorry for the delay in my reply, it finally stopped raining here in Mid Ga. and I've been busy as heck. Again thank you guys so much I've been away from the forum for several months. Good to be back....

drobertson

What I've seen in a few short years of sawing custom is that folks have a limited number of logs for a given cut list. And the order is expected for the most part from these logs.   The best that can be accomplished comes from a few years of trial and error.  In my case there are very few options with timing or scrapping of the timbers..  So, as mentioned, when one gets to a 5x5 or 6x6, whatever the size may be,  the beam or post as called will have the early growth, which is most often fast growth, will bow and twist, and the longer the beam the worse. My experience only, others may say otherwise.   Flipping, and trimming with some waste to get a green beam to size is the only way I have found to produce the product.. this although will not guarantee a straight post when subjected to sun and wind and drying for very long.  So, If sawing oversize, then finishing is acceptable then do it, otherwise, these beams are what they are, pretty simple, just not always pretty,,, ;D  not much else to say about that,,
only have a few chain saws I'm not suppose to use, but will at times, one dog Dolly, pretty good dog, just not sure what for yet,  working on getting the gardening back in order, and kinda thinking on maybe a small bbq bizz,  thinking about it,

bkaimwood

Curious and new... But...depending on the size....a 6x 6 in only white pine will support almost 5 tons vertically, on its own...so even in substandard grade, cutting it in half, is still plenty? On to bowing...proper bracing will minimize thus?...back to the age old comment...barns were put up green, braced accordingly, and even the shoddy ones stood for longer than I'll live....no facts here, just thoughts and opinions from a newbie...I read a lot...
bk

beenthere

Jim  per reply #9
QuoteLumber grading rules usually state that any timber over 5" x 5" should be boxed heart/pith centered both ends for strength.

I can access the NDS, but do not find where it says anything about boxed heart when over 5" x 5". Can you find it and point it out for me. Would appreciate it.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Jim_Rogers

Quote from: beenthere on May 08, 2015, 09:47:54 PM
Jim  per reply #9
QuoteLumber grading rules usually state that any timber over 5" x 5" should be boxed heart/pith centered both ends for strength.

I can access the NDS, but do not find where it says anything about boxed heart when over 5" x 5". Can you find it and point it out for me. Would appreciate it.

Maybe, I'm mistaken. I can't find it either in my NeLMA grade rule book.

I'll have to do a little more research and see if I can find it.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

beenthere

Jim
It probably is a good practice to follow, just that I was surprised when you said a rule stated such. 

If you do sometime run across where you might have seen it, I'd appreciate its source. Thanks.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Jim_Rogers

Quote from: Jim_Rogers on May 09, 2015, 07:28:25 AM

I'll have to do a little more research and see if I can find it.

Jim Rogers

Ok so to research my statement which was NOT correct. I emailed NeLMA and asked them:

Is there a grade rule that says any timber over 5" x 5" should be boxed heart?
If so what is the section number?
If not is it just a common knowledge "good practice" procedure?

Here is their reply:

There is not any such rule that states the heart should be boxed; it's simply a preference. Typically, in northeastern species the heart is boxed more often than not, simply due to log sizes not capable of yielding large timbers free of heart. Most often pieces free of heart will develop significant bow and twist during seasoning, which is a reason some request the heart to be in the center of the timber, as the stresses are relieved equally around the piece during drying/seasoning. 
"Free of heart center" is a common product in larger western species such as Douglas Fir. 
Hope this helps.
Thank You,
Matt Pomeroy
Director of Inspection Services
Northeastern Lumber Manufacturers Association (NeLMA)


Sorry about that Beenthere.

Jim Rogers
Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

beenthere

Not a problem Jim. Thanks for checking it out for us.
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Ljohnsaw

Quote from: Jim_Rogers on May 11, 2015, 09:14:38 AM
<<snip>>
Here is their reply:

There is not any such rule that states the heart should be boxed; it's simply a preference. Typically, in northeastern species the heart is boxed more often than not, simply due to log sizes not capable of yielding large timbers free of heart. Most often pieces free of heart will develop significant bow and twist during seasoning, which is a reason some request the heart to be in the center of the timber, as the stresses are relieved equally around the piece during drying/seasoning. 
"Free of heart center" is a common product in larger western species such as Douglas Fir. 
Hope this helps.
Thank You,
Matt Pomeroy
Director of Inspection Services
Northeastern Lumber Manufacturers Association (NeLMA)


Jim Rogers

Jim (or any others that want to chime in),

Since I will be milling "larger western species" when I get to my cabin, how far from the pith should one go for FOH beams that are "large".  I'm just trying to imagine my cut plan - get a few beams (10x16, 8x16, 8x15, 8x12) and rafters (5x9) out of a 30-40" DBH (one boxed heart, a few FOH) and some side wood (4x6 braces, 2x4 studs) between them?  Hope this makes sense.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

beenthere

FOHC (Free of Heart Center) means "without pith".

Source: WWPA (Western Wood Products Grading Assoc.)
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Ljohnsaw

BT,
Not sure if you were replying to my question.  I know what FOH(C) means, what I was trying to say is, how far should one cut so that the resulting beams are the most stable - least likely to warp, etc (I know, they will do what they want to do...). 

Also, the wood (if there is any) between the heart centered beam and the FOHC beams is most suitable for/should be cut into xx stock that would season reasonably well.

Pictorially - bark (FOHC) (FOHC) xx (HC) xx (FOHC) (FOHC) bark

Or just maybe the FOHC will be abutted to the HC beams without issue?  If it is an issue, it seems like it would be more of a percentage of the diameter vs. a specific inch measurement.

Hopefully I didn't make my question more obtuse.  Its just that when I do get cutting, I don't what my beams to end up as firewood.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

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