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Box heart or split cut?

Started by Beetlekill, March 15, 2011, 03:46:20 PM

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Beetlekill

Hello all,  I have a pile of spruce logs that I am working on cutting into timbers and stickering in my pole barn for a future build.  Many are around 20 in. on the butt and make and make 12x cants.  I have been making three 4x12's from each and I need to make some 6x12.  Is it acceptable to make two of these per cant or is the norm to take off smaller boards until there is a box heart 6X12.  Also, If logs or cants(softwood) have already begun to season and have some end checking, is it necessary or advised to still treat ends with an end coating product.  Most of my timbers are around 20ft - so I will most likely be trimming at least some wood off of the ends before use.   Thanks for any advice - Brian.
   

Ron Wenrich

Whenever I have the option, I go for boxed heart.  I worked with some white pine 6x8's cabin stock that was split heart, and it bowed.  And, that is normal when you split hearts.  Some will stay straight, some will bow. 

Given your sawing pattern, you might be able to get a 4x12 and a 6x12 off the same log and still have a boxed heart in the 6x12.
Never under estimate the power of stupid people in large groups.

bandmiller2

Beetle,alot depends on what your going to build.If your building where straight is important box the heart as Ron says.If your building rough barns and sheds, get the most out of each log and put crown up to the load.If you need boards for boarding in then its no loss to box the heart. Frank C.
A man armed with common sense is packing a big piece

northwoods1

I'm no expert carpenter but I have done a fair amount of building with pine beams for floor joists, rafters & trusses etc. and what I have noticed is that if you have a box heart the beam will split to the heart almost every time without exception. If your using a species that shrinks a fair amount this crack can open up a significant amount depending on the size of the beam. That can warp the timber quite a bit and take it out of square. But if the heart is not left in the beam, like Ron said a fair amount of the time you won't get to much warping especially if they are stacked and stickered in a way to prevent that as much as possible until use. And when you build with them, for instance if they are going to be floor joists, if you put them in place and install blocking at the ends where they are supported so they are physically prevented from moving and then fasten a floor down on top of them out of 2" decking or whatever your going to use they will not move. But if they have the heart in them they can continue to dry out over the years and that crack to the heart can open up significantly in particular during the winter when things get real dry. So what I am saying is if you don't have the heart in the beam it might warp but there are things you can do to prevent that, but if you have the heart in it there is nothing you can do to prevent it from cracking to the heart and even if it is installed that seasonal shrinking that will occur is quite a strong force working to pull it out of place even if securely fastened. That is just my observation and I should add that I have 7-8,000 bf of 16' pine logs that need to get sawed into timbers for a future building project so this is something I have been giving some thought to lately :) :)

beenthere

northwoods
Are you talking about red and white pine?
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

Brucer

I rarely saw spruce so this will be generic information about sawing beams. Most of my work is sawing Douglas-Fir timbers for contractors and timber-framers.

As a rule, unless the customer specifies otherwise I always saw 5" and smaller FOHC (Free of Heart Centre). For 6" and up I box the heart.

For FOHC I always try to leave at least 1" on either side of the pith -- the heart centre is soft and may do strange things when it dries.

Ron mentioned that when you saw out the heart the timbers can bow. The timbers always bow away from the centre unless the log has some strange stresses in it. This is generally true for all species but it varies a lot. Douglas-Fir only moves a little, Western Red Cedar moves a lot.

When I'm sawing short D-Fir beams, I don't worry about it. For longer ones I square up the cant, cutting it 2" oversize in one dimension and keeping it centred on the pith. Then I split the cant down the centre and park one piece off to the side. The other piece I sit on the mill with the heart side up (the centre of the timber will be up off the bed of the mill). I trim off the top to get rid of the heart and give me a flat surface. Then I flip it over and saw off the "ears".

You will waste wood this way but you will get some excellent beams. I always charge more for FOHC to account for the waste. If you're sawing for your own use, you might be better to just saw your cant oversize and then split the heart. When you're ready to use it you can true it up and take out any bow.




Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

Beetlekill

 Thanks alot for the input.  Since these beams will be for my use I am leaning towards getting two 6x12 per log.  I should add that many might be resawn in the future into something else.  I have sawn many 8x8 that were box heart that checked fairly drastically to the pith which made them somewhat useless to resaw.  Basically, I have about 30 nice logs that need to get cut before they degrade,  my thoughts being that beams without heart would be the best way to store these for future use as a framing timber or for resaw into something else.  I will cut some box heart 8x12 as well,so I guess I'll have learned what worked the best for these logs in a few years.  May is our dryest month, and I dont want to see the logs crack open before I cut them, they've already been stacked for a year and a half.  Brucer (or anyone)- when you sell timbers is end sealing something that  is necessary,  I've never done it to my wood so I dont know if it would reduce overall checking?  Woodmills- good luck with your pine logs,  I speculate that the spruce I cut reacts similar to the pine as it drys.  Thanks again, Brian   

Brucer

I sell timbers cut to order for timber-framers. I don't end seal the timbers because they will be cutting and doing joinery on the ends within a few days/weeks of getting the wood. Once they've done the joinery, they will end seal every cut surface in the piece.

My logs at the end of the season may have some checking and I will usually cut timbers a foot over length so the customer can trim it out.
Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

isawlogs


Ihave sawed many many thousands of feet into beams, boxing in the heart was done on the smaller logs , on the bigger ones , well we got as much beams as possible from the log. If the beams did go warpy on us , we just cut them into boards and cut another beam , not all the beams will warp if not boxed in , only a small percentage , so I would go and saw the most out of a log and deal with the warp as it shows up.
  The logs that have any sweep to them , I can assure you that it will warp. ( boxed or not)  ;)
A man does not always grow wise as he grows old , but he always grows old as he grows wise .

   Marcel

Magicman

Quote from: isawlogs on March 17, 2011, 08:55:49 AM
  The logs that have any sweep to them , I can assure you that it will warp. ( boxed or not)  ;)

Absolutely.  Just boxing the heart will not insure or guarantee you that the beam will not warp.  You will have a failure rate, no matter how you saw it.  That is determined by the log, not your sawing method.  Sweep and stress does bad things to good lumber.
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

WDH

I am not experienced in sawing beams, so let me get that out right from the start.  I am just trying to take a general understanding of wood and think through how a sawyer might eliminate as many problems with thick stock as possible.

It stands to reason, given how wood behaves, that sawing a beam from a log so the the growth rings are as consistent in width and orientation will yield a beam with the least potential drying stress.  Conversely, a beam with the pith on one side, with the wide growth rings when the tree was young and fast growing on one edge, and the other edge, the narrow rings of older, slower growing years, would have a great deal of wood properties variation across the width of the beam, likely setting up all kinds of tension and stress.

The wood of early, fast growth for the first 10 years or so, is called juvenile wood, and it has different properties than wood produced when the tree is older, which is called mature wood.  Very wide boards naturally have some of both types of this wood in them, and they can tend to cup.  Also, boards cut perfectly radially where the pith is exactly on one side and the outside of the tree is on the opposing side almost always end up with a distinct side bend or bow.  The properties of juvenile wood are not very nice to the woodworker and carpenter.

With very large beams, boxing the heart is probably best because you have few options.  For smaller beams, it stands to reason that producing the beam from the portion of the log where there is the least juvenile wood and where the growth ring pattern and width is the most consistent would produce the best quality if you did it a million times.

But, I am not experienced sawing beams, just trying to think about the beam challenge using wood logic.
Woodmizer LT40HDD35, John Deere 2155, Kubota M5-111, Kubota L2501, Nyle L53 Dehumidification Kiln, and a passion for all things with leafs, twigs, and bark.  hamsleyhardwood.com

bandmiller2

Sawmills cut "rough cut" lumber,the only way I know how to cut straight accurate beams is to cut over long and over size, dry/cure then recut to specs.  Frank C.
A man armed with common sense is packing a big piece

sigidi

Quote from: Magicman on March 17, 2011, 09:45:30 AM

Absolutely.  Just boxing the heart will not insure or guarantee you that the beam will not warp.  You will have a failure rate, no matter how you saw it.  That is determined by the log, not your sawing method.  Sweep and stress does bad things to good lumber.

I think I'm gonna get a sign made up of this little gem MM and hang it near the mill so I can point at it when questioned about "what I did to the timber"  ;D ;) :D
Always willing to help - Allan

Brucer

"Ask not what you did to the timber. Ask what the timber did to you."  :D

With apologies to JFK.
Bruce    LT40HDG28 bandsaw
"Complex problems have simple, easy to understand wrong answers."

shinnlinger

When I cut my latest timber frame, I was cutting what I needed from what I had from windblown salvage.  What thet meant is I would roll a log on the mill and decided what I could most eficiently get out of it.  By the time I got to 6x7 purlins and 4x8 floor joists I still had 16+ DBH logs, so guess what?  I would cut 3 or 4  out of one log if I could.  Now this was before I knew better because I hadn't joined this site yet, but everthing turned out fine.  Airdryed in stacks worked well for me.  I hear kiln drying white pine causes alot of the cupping and warping vs letting it air dry.  I don't have a kiln so I don't know, but I split heart w/out issues.  If that is the most efficient way to get what you need, I would do that.

Dave
Shinnlinger
Woodshop teacher, pasture raised chicken farmer
34 horse kubota L-2850, Turner Band Mill, '84 F-600,
living in self-built/milled timberframe home

terrifictimbersllc

Quote from: Brucer on March 18, 2011, 05:30:31 PM
"Ask not what you did to the timber. Ask what the timber did to you."  :D

With apologies to JFK.

Should be allowed to have a trial and execution on the spot.  Sawyer's choice of methods.
DJ Hoover, Terrific Timbers LLC,  Mystic CT Woodmizer Million Board Foot Club member. 2019 LT70 Super Wide 55 Yanmar,  LogRite fetching arch, WM BMS250 sharpener/BMT250 setter.  2001 F350 7.3L PSD 6 spd manual ZF 4x4 Crew Cab Long Bed

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