How Much Oversize to Cut Beams?

[Kicker_92]

I've searched the archive, and found lots of info about how oversize to cut planks and small stock, but little info on large beams.

I need to have a finished 18" x 6" x 32ft beam that is straight and not twisted when fully finished. I'd plan for about 0.25" on each face to take out for milling marks, but how much more oversize should I cut so that we can take out any bow or twist when finished drying?

The wood is Douglas Fir, and I have a 32" diameter x 40ft log to cut it from, so was planning on sawing FOHC.

 

[FJH]

I've searched the archive, and found lots of info about how oversize to cut planks and small stock, but little info on large beams.

I need to have a finished 18" x 6" x 32ft beam that is straight and not twisted when fully finished. I'd plan for about 0.25" on each face to take out for milling marks, but how much more oversize should I cut so that we can take out any bow or twist when finished drying?

The wood is Douglas Fir, and I have a 32" diameter x 40ft log to cut it from, so was planning on sawing FOHC.

Unless the tree is 6 ft across your going to have a bear of a time keeping it straight leave lots My advice is if you can get the sap wood off then let it dri then remill it.Its hard keeping a 16 ft beam straight never mind 32 ft!

 

[Mike Van]

A beam that size is going to take years to air dry, with no guarentee it's going to be what you want when dry. At least one face will check to the heart as the stress changes. I think it's too much to hope that something that size will be as true as you want it. Probably why they make glue-lam beams, they won't change the way a real one will.

 

[SilverBox]

I've searched the archive, and found lots of info about how oversize to cut planks and small stock, but little info on large beams.

I need to have a finished 18" x 6" x 32ft beam that is straight and not twisted when fully finished. I'd plan for about 0.25" on each face to take out for milling marks, but how much more oversize should I cut so that we can take out any bow or twist when finished drying?

The wood is Douglas Fir, and I have a 32" diameter x 40ft log to cut it from, so was planning on sawing FOHC.

I think its doable, I'm planning to slab off some doug fir 25' long (the cant will be about 20"x20") in 6" slabs then stack it up and let it dry, I don't anticipate alot of twisting or shrinking. In a year or 2 I plan to use that wood to build a post and beam barn.

If I were to take a guess at it, I'd imagine less then 1/4" shrinkage in the 6" dimension of your beam and less then 1/2" in the 18" dimension, but I'm no expert, just an experimentalist

 

[Sawyer Rob]

I've searched the archive, and found lots of info about how oversize to cut planks and small stock, but little info on large beams.

I need to have a finished 18" x 6" x 32ft beam that is straight and not twisted when fully finished. I'd plan for about 0.25" on each face to take out for milling marks, but how much more oversize should I cut so that we can take out any bow or twist when finished drying?

The wood is Douglas Fir, and I have a 32" diameter x 40ft log to cut it from, so was planning on sawing FOHC.

Every tree is different, so every answer here will be a rough guess...

Your best chance for success is the make sure you "center" the heart, and even then i'd be surprised if will be perfectly straight without some twist over 32 + feet...

If it was me, i'd leave several inches in both directions, i mean what the heck, you have plenty of tree, and you have to resaw it anyway...

Rob

 

[Kicker_92]

If it was me, i'd leave several inches in both directions, i mean what the heck, you have plenty of tree, and you have to resaw it anyway...
Rob

I'd like to mill it oversize and process it down later, just trying to figure out how much. I have no problem making it a 22"x8" if thats what it takes to re-mill to a 18"x6", just don't want to waste more wood than I have to.

It's a hard descision to either center the heart, or cut free of heart center. I have a larger 36" diameter log that I could use instead. These a pretty tight rig second growth Firs, they should be quite stable. Just want to avoid hacking of a section that will dry and not be resawable.

 

[Sawyer Rob]

It's not a hard decision for me... CENTER the heart, it's your best chance of a straight beam... Then leave enough on all 4 sides to get a 2x out of the cuts later... That way the 2x's coming off, won't be wasted...

Rob

 

[FJH]

I'd like to mill it oversize and process it down later, just trying to figure out how much. I have no problem making it a 22"x8" if thats what it takes to re-mill to a 18"x6", just don't want to waste more wood than I have to.

It's a hard descision to either center the heart, or cut free of heart center. I have a larger 36" diameter log that I could use instead. These a pretty tight rig second growth Firs, they should be quite stable. Just want to avoid hacking of a section that will dry and not be resawable.

Ive cut into fir logs that looked real stable too and had peices come off there that looked like the leaf spring of a mack truck specaily butt wood.Its a crap shoot! leave lots like sawyer said leave 2 inches if it stays straight you got useable peices later Also you have 32 inch at 32 ft? or is that the but end?

 

[Kicker_92]

leave lots like sawyer said leave 2 inches if it stays straight you got useable peices later Also you have 32 inch at 32 ft? or is that the but end?

I actually have 32" at 42ft, I think it's around 40" at the butt end, but I'll cut the log down to 32ft to mill it. It's about 5200kg right now, so a bit ackward to move around.

I really like that idea of leaving a 2x after shrinkage and kerf. I could center the heart and saw it to 23" x 9" and still trim off all the sapwood.

Thanks for all the input, this'll be a fun one!

 

[MR4WD]

Post pics!

 

[Kicker_92]

Here's one teaser shot. We'll get to milling it up in a couple of weeks.

 

[Matildasmate]

When drying your beam , it is important to make sure the beam is stacked flat and plenty of weight on top of it , I have got a pack of dry timber about 2 ton stacked on top of my last batch of milled timber , makes a big difference to the Quality of the timber when dried . Cheers MM

 

[dallasm1]

Those are AWESOME timbers. Any chance you have any left over?

 

[Kicker_92]

Those are AWESOME timbers. Any chance you have any left over?

We'll be using them to build out house, a total of 62m^3 uncut (around 20,000 bdft). I will probably have 20% overage one we are done, depending on how they all turn out, but there's allways sheds etc to build one the house is done.

 

[DRB]

Sure would be nice to get free of heart. Is the log big enough to cut a 22x20 centered heart? You could cut one 22x8 free of heart then cut out the heart with a 22x4 and be left with two 22x8's. You might want to cut more than 4" out of the center to be sure you get all the center out. Stack these on the bottom of your pile out of the sun and continue to stack the rest of the cut up log on top and leave them there for two years. The 22x4 would make some nice VG Doug Fir trim? This way you would have 2 beams to chose from. This may be a little wasteful but a FOHC beam of that size would be worth lots of money.

I cut these 4x12 last fall and they have shrunk less than 1/4"

Gotta love FOHC Doug Fir

Good luck be sure to post pics

 

[Brmorgan]

Douglas Fir will shrink about 4% radially from green to dry. So SilverBox's guess of 1/4" in 6" is very close to the actual calculation of 3.84 sixteenths of an inch. Likewise over the 18" section you could expect a shrinkage of about 11/16" or so, a bit more than 1/2". As for the warping though, good luck. And as already pointed out, it'll take years to dry. The 20' beams I milled for my deck last summer were cut from dead trees, but were not seasoned at all before use. They weren't wet but they weren't very dry either, and have dried in place. They've stayed pretty straight, but being secured with 6" lag bolts in a couple dozen places probably helps.

 

[MR4WD]

I cut an old growth fir, about 40" dbh, clear up to a 100' with the top blown out at about 125' (still about 24" dbh) standing dead and drier than a northern winter last year. No bugs in it, not rotting, standing there waiting to be milled. Super dry. I was carefull when I dropped it too, I only lost about 10' of wood (from the impending crack)

Made some excellent firewood, but I kick my a$$ when I think what I could have made out of that (on the quick) if I milled it.

I checked the region today, since it's then first I've been able to make it up there since the snow went... There's still some old general's left. But most have went to bugs or are still green.

Now I'm in the market to mill some long cants and I can't find dry decent fir anywhere...

Like I said, post pics of your milling project/setup

Chad.

 

[Kicker_92]

Sure would be nice to get free of heart. Is the log big enough to cut a 22x20 centered heart?

I'll have to measure it once we have cut to length. We'll make most of out pieces without any sapwood, so I'm not sure how deep that will go until I cut it to length.

...leave them there for two years. The 22x4 would make some nice VG Doug Fir trim?

We won't need these for two years, possibly even three. I'm trying to saw up all the wood we'll need now, so I can stack & sticker it outside for two years, and for any pieces resawn as trim, stack them inside for an extra year.

I think for the trim I'll slice up some of the bigger sections and rotate / quarter saw them. I'm limited to a 34" wide cut with the Alaskan & 41" bar anyways. Thanks for the tips, and nice 4x12's!


First we'll trim up the ends and paint them, they've already sat for 6 months in the sort yard.

 

[Brmorgan]

Now I'm in the market to mill some long cants and I can't find dry decent fir anywhere...
Chad.

Road trip? I could show you quite a few big dead ones around here that are fairly easily accessible. Not too many around 40", but I've got my eye on a half-dozen in that size range just a stone's throw behind my dad's house, a couple of which must be around 5' with the bark on. Easy to get to on the quad, but it might be hard to get long timbers out without a log arch.

As an aside, what's your aversion to cutting bug-killed trees? There's nothing wrong with the wood, especially if it's only been dead a year or two.

 

[dallasm1]

My mouth is watering looking at those beoooootiful Doug Firs. I also am in the market for long big DF, but heck... who isn't? Any road trip would need a logging trailer with a self loader just to pull any of those out! (alas, I do not have one of those) Brad let me know if you need help with those firs, you aren't that far north of me.