beams

[SDM]

hello all, I`m back for more knowledge...hope to start delivering some photos of my progress, lumber, mill, and plans for my large poll barn, but for now I need to know about beams. I have a large supply of 20+ in. syp logs. Can I make multiple 8x8, 6x6 beams outa the same log or do I need to always keep the heart centered in my beam; therefore only 1 beam per log? Thanks

[ErikC]

  Heart center beams are not stronger, less in some cases, and more prone to twist. So start cuttin'.... 8) 

[ohsoloco]

Timbers that don't have the heart boxed are more prone to bow.  Jim Rogers did a nice job explaining this:

https://forestryforum.com/board/index.php/topic,4247.0.html

[Magicman]

If you can use that "side lumber" in your barn building, then I would box the hearts.  Although stress in the logs could cause them to do "bad" things.

Another option, and certainly worth considering, is not to actually use solid beams.  Saw it into 2X8's and 2X6's and then spike them together.  Especially using "grade" sawed lumber, the beams will be stronger and more stable.

[ARKANSAWYER]

  One log, one beam or post.  Any thing larger then a 4x6 should be centered on the pith of the log.  You will get less grief that way with SYP.
 Also try to cut the timber from the size log that is not to large for the purpose.  Like a 8x8 post comes out of a 12 inch log just fine but one from a 24 inch log is not as good.  6x6 out of a 9 inch log and a 6x16 out of a 20 inch log.  Also try not to have the bottom 8 ft of the log in the timber.

[Magicman]

Also try not to have the bottom 8 ft of the log in the timber.

Very good point !!!   Compression stress is a bad thing in lumber as well as beams.

[captain_crunch]

I have always heard to box the heart for beams. But like Majicman says multiple boards spiked or bolted are really stronger as in Gluelams. But I kinda did mine right by accident A 6X6 10 ft long with Sapwood is TOO heavy for me to horse up onpost ;D ;D ;D ;D

[beenthere]

.......
Very good point !!!   Compression stress is a bad thing in lumber as well as beams.

More accurate to refer to it as compression wood. That wood will shrink along the grain, whereas normal wood does not when it dries. 
Compression stress usually refers to the load stresses applied to a member.

Just extraneous info. 

[Magicman]

I'd much rather a customer cut the stump high or "jump butt" the log before bucking it up.  Those large SYP logs that are cut off at ground level will sometimes turn a sawblade.  That compression wood is some hard stuff.... >:(

[SDM]

compression.... I always wondered why the blade slowed down at the end of the cut. Too bad I`ve already cut several beams using the bottom part of the tree. It would make sense that u would get more twist & shout from beams cut any other way than boxing the center. So whats the best use for 100+ yr old syp approx 36 in dia.?

[moonhill]

I use the butt logs often in framing material, the butt goes up and the flare allows for more joinery which is needed at times.  So, sometime the butt log is desirable.  Also, if you are looking at long timber you want all the fat you can get, the top may wane off.  When looking to box the timber look at the top end not breast high.  Where is the 20"?  If it was a 20" top I would be tempted to cut 6x6s out of them, maybe even 8x8 depending on how much they will bow. 

Tim 

[Tom]

I've sawed a lot of "timbers" from Syp, without boxing the heart, and they worked just fine.  As a matter of fact, if the beam is turned such that the grain is vertical, it will carry a lot more weight and be less prone to breaking than if the grain is horizontal.  Checking doesn't seem to be as bad as checking in a boxed heart timber either.  The timber cut from the side of the log does have the tendency to bend, but sometimes it does it and sometimes it doesn't.  Boxing the heart eliminates the bending because the internal tensions counteract one another.  I don't think I would waste a 36" tree just to get Boxed heart, if it were for my own pole barn.   Loblolly is the worse for drying crooked.  Weight on the drying stack helps a lot.  Make the stacks narrow so that the weight of the timbers helps.  Or, you could put them up fairly green and hope that the structure holds them straight as they dry.  

My pole barn has 2x12's laminated together, heart to heart, with some Elmer's glue snaked in between and then spiked with 16p nails driven at angles from each side.  I imagine it well be there a long time after me and the tin roof are gone.  

[shinnlinger]

Try to get your whole cut list worked out before milling.  I only figured what I needed for the timbers for my timber frame and always tried to box the heart and I made a lot of boards and 2x in the process (and got a workout with the peavy on my manual mill).  NOw that I am finishing my house,  I am burning up all the "Bonus wood", but I would have been more efficient if I knew ahead of time that I needed more 1x10's or 2x6's or whatever.

I will now have to mill some more at some point even though I will still have left over wood of the "wrong" variety.  NOt that this is a terrible thing as I have storage space and will use it at some point I am sure, but it would have been more efficient and would have been working with more seasoned wood if I had thought ahead better.

Usually the compression wood is pretty clear and makes better boards anyways, but get then properly sticker stacked.

Dave