Half Taper Sawing

[4x4American]

So, in the Aug/Sept 2015 edition of Independent Sawmill and Woodlot Magazine (if you don't subscribe you should) there is a good article called, "Let's 'Face' the Facts About Sawing."


In it, a thing called "half taper sawing" is discussed.  Half taper sawing, basically, is when you saw only half the taper out of one face (and get the rest out on the other half).  Full taper sawing is when you cut parallel to the bark on the first (and second) face.  It is said that full taper sawing produces more valuable lumber that is less prone to warp.


Here is where I ask for your input.  I like to keep the pith level to the bunks.  Now, when you level the pith on the opening face, essentially, you are half taper sawing.  If you full taper saw, I don't see how you can level the pith without taking a tapered burn board later on.  I can see how full taper sawing would be faster, but I don't see how you are to level the pith, without wasting lumber. 


How aboot that one, eh?

[Ianab]

The idea is that your best boards are first ones from the outside of the log. The ones near the pith tend to be lower grade, with juvenile wood, knots, pith and heart cracks.

So if you level the pith, your waste wood is the heavy wedge shape slabs you take off to get your first face, and that's top quality clear wood. Then your last boards are low grade from around the pith.

If you cut parallel to the bark, you should improve the grade of the boards, and the waste is a wedge shaped chunk of low grade wood, that wasn't worth much. Amount of waste is similar, but one wastes clear wood, the other wastes knotty rubbish.

Now this only works if you are sorting and selling by grade. If you sit down and compare the graded yield, and find the lumber is worth 10 or 20% more, then there is an argument saw that way, even if it takes a little longer.

If you are just selling the boards ungraded, or grade doesn't matter, then just level it up and cut the most efficient way.

[4x4American]

Ok that makes sense!


I mainly saw pine for un-graded construction lumber so I guess it doesn't much matter, but good to keep in mind when I do saw hardwoods for woodworkers.

[beenthere]

But 4x4, keep in mind that for your construction lumber (dimension), there will be less warp and higher strength if the grain of the piece is straight with the edges. So parallel to the bark and in the outer wood may matter in what you are sawing.
But agree, still ends up with what quality a person is satisfied with in the end as well as what quality lies within the logs being sawn.

[Percy]

Cutting Western Red cedar, which often has a rotted pith, I've tapered on all 4 faces ending up with a Washington monument shaped "left over". Works well.

[4x4American]

Yes, that was a good but, but, a lot depends on the log.  Sometimes a knot will be worse in the outer wood and not bad in the inner wood, sometimes it goes right to the center, and other times it doesn't make a difference anyhow because it's centered in a wide 4/4 board that's gonna be for siding or such. 


It seems to me that it would be quicker to full taper saw, if I didn't have to adjust for the pith to be centered later on. 


To turn off the subject a little bit, how many of you, when you're sawing through a cant or three, and see that the pith isn't going to be avoidable, just keep sawing?  When you go look at the box store lumber, very many pieces have the pith split in them.  Is it that a serious sin to split the pith?  I try to avoid as best I can without getting out the micrometer.  One can waste a lot of time by being overly picky about the pith.  For me, if I'm on a portable job, I'll tell the customer about splitting the pith, why it's not great, and to check the pieces he's using in important applications.  If I'm sawing at home, often times I'll put the pith split pieces off to the side for either my personal use or for lower grade applications.  Am I wasting time by being so picky with the pith?  Who gives a pith anyways?

[Ianab]

The question is, will the board with the pith included, or split, be a reject that you don't get paid for, or can't use. If you are building with your own wood, as you say, you can put those dubious ones aside and use them for less critical uses. Those boards aren't as strong or as stable, but if you are only building a chicken house they will be fine. For your house roof trusses? Maybe not.

If it is, then you take a bit more care to try and keep it in one small waste piece. If the included pith is acceptable in the end use (ungraded construction lumber or fence boards?) then just saw it however is convenient.

The big cypress logs I often cut will always split for an inch or 2 around the pith, so that board is generally useless. So I try and keep the pith in one board, and just chuck it on the firewood pile right away. But cutting small Port Orford cedars, you can cut 4x1s with small tight knots and the pith wandering in and out of the board, and they are fine.

Like Percy says, other times you have that rotted core that you taper saw around to get the best return.

So there is no "one rule fits all". It's about knowing those idiosyncrasies of the different logs and end products, and the best method for dealing with them.

[4x4American]

Thanks, Ianab!  Good stuff.  I hope this information benefits more to come.

[WDH]

The pith is not a big issue in some species, and in others, it is a big issue.  In pine, the pith is not a problem.  Does not crack or split.  Just saw for the best grade boards and let the pith fall where it may in Pine.  Except for one thing.  Never saw boards that have the pith along one edge of the board.  This will cause the board to crook into a C-shape and make it unusable as construction lumber.  In boards that include the pith in pine, always try to center the pith in the boards. 

Now with the oaks and cherry, the pith will always crack and split, so leave it in a 4x4 in the center of the log and use it for dunnage or stacking stuff on, or, edge the pith out of any good boards.  If you leave it in the center of a board, the pith will crack and split, so, to get the good wood on either side, you have to cut out the pith anyway.  If you are using the board yourself, you can leave the pith, dry the board, and rip out the bad cracked center when you use it.  If you are selling grade hardwood boards, those are the ones that the customers pick through and reject, so to sell that wood, you have to end up cutting out the pith anyway.  Figure out when is the best time to get rid of the pith in these species to make it most efficient for you.  Personally, I hate to spend time drying board footage that I will discard later anyway. 

[4x4American]

Thanks WDH

[dboyt]

The boards with the pith have vertical grain (quartersawn), which also gives them potential value.  I set these aside for woodworkers who want the quarter sawn wood and are willing to cut what they can out of the split boards.  I charge the same for the wood with pith in it, even if it is split, and have no problem selling it.  Even pieces like this (walnut).



 

[drobertson]

This is going to come off with a bit of a smart @@$ tone, but I have to say it, I saw half taper on most every log that needs it, whether it is pine, oak or other,  I would really like to know how folks that grade can tell if a board has been sawn from a log that has been sawn from a either of the two.  From what I've seen in the grading process it is high speed, low drag, looking for defects not whatever is mentioned in parallel to the bark or any thing else, just asking I guess.  I look for maximum yield from the log, with the longest useable board.  Please help me If I am missing something here,,   

[beenthere]

I'll give it a stab.
Usually stress grading is done now with a machine that measures MOE (modulus of elasticity) by either bending the piece and measuring the resistance or by sending sound through the wood and measuring the speed. Both indicate MOE character of a piece, and the MOE of straight grain will come out higher than if that grain is not straight. The straightest grain will be when sawing parallel to the bark.

This doesn't mean that there are not a lot of other things that don't also affect the strength of a board such as knots, crook in a log, sweep in a log, spiral grain, among others.

As well, a lot of log sawing practices don't lend themselves well to sawing an entire log parallel to the bark and removing taper elsewhere within the log. However, some of the portable milling rigs we discuss on the forum can lend themselves fairly well with the help of toe boards and hydraulics to do it easier.

[drobertson]

Not a bad stab, but there's none of that in our grading around here, I am going to say I still think a lot of it is bo donk,  I am really very uneducated on it, but if I could see it then I might be a believer, 

[Ianab]

The boards with the pith have vertical grain (quartersawn), which also gives them potential value.  I set these aside for woodworkers who want the quarter sawn wood and are willing to cut what they can out of the split boards.  I charge the same for the wood with pith in it, even if it is split, and have no problem selling it.  Even pieces like this (walnut).

If you are selling individual pieces of wood to woodworkers, then yes, someone will look that that "board" and think, "Cool, I can make a $300 table out of that", and buy it. Everyone's happy with the deal, so it's all good.

But if you are a selling wholesale according to grade, there's not even a class for that..  :D

I would really like to know how folks that grade can tell if a board has been sawn from a log that has been sawn from a either of the two.  From what I've seen in the grading process it is high speed, low drag, looking for defects not whatever is mentioned in parallel to the bark or any thing else, just asking I guess.

The best boards in most hardwood logs are usually the ones on the ones from the outside. Taper sawing means you hopefully get a couple more high grade boards. Even with that brief glance the grader gives it, they can tell a "Clear" from a "Knotty and pith" and you are paid accordingly. So getting 2 more FAS grade boards, and loosing 2 "pallet grade" puts more $$ in your pocket. On close inspection the exact angle of the grain through  the board might show how it was cut, but doesn't usually affect the grade.

But if you get paid the same as long as it's any decent board, then saw it the easiest way. You aren't earning any more for the extra messing about.

[beenthere]

drob
You are correct in that you will not see that grading... it is done in big mills at high speeds. The top end of the strength spectrum is creamed off and heads off as engineered lumber for the laminated beam and truss manufacturers, whereas the lower end goes to the box stores.

But if'n none of that is important to someone sawing their own wood, then sawing any way desirable is good enough for who it is for.  ;D

[drobertson]

you bet, thats' the way I see it, I have been screwed if this is ok to say by the graders, cream of the crop, with no reward, until I speak up, it holds for a time or two then back to the same ole grind, I will stick to custom sawing, a pain, but very rewarding in more ways then cash in the pocket,  all I need to do now is tap into the Georgia market and make a deal with folks that want a deal,, shipping is the only killer,

[bkaimwood]

I've really enjoyed this post so far, especially the last handful...many good points, and I still have alot to learn... I saw split taper, or center pith on all logs...there's good points to both, but for me, it works... I saw alot of softwoods, which don't have pith issues like for instance, oak...so I look for stability in the lumber, and many times may be sawing for boards on the outside, and a beam or beams in the middle... It takes a hair longer this way to be anal with centering the pith, but worth it...I'm getting into lots of oak now, and am doing mostly quartersawing... So again, perfect opportunity for the best quartersawn end lumber...box the center/pith, throw it in the firewood pile, and quartersaw everything from there...I was sawing the pith out after drying, but find that eliminating a step, and handling lumber one less time for me makes sense...it also pays off because when a potential buyer comes to look at your lumber, its prettier... And I think it might cause less stress in drying stacks?

[Engineer]

I read that article and it was educational, as I'd really never understood why certain logs should be sawn certain ways.  When I had my mill, all of my hardwoods were basically butt logs out of firewood trees, so I sawed them to produce lumber that looked most appealing to me.  I have sawed a few "washington monuments" out of nice clear logs with a lot of taper, leaving the pith for firewood, basically.  You do tend to get better grade boards, with more consistent grain, if full-taper sawed. 

On the other hand, almost all of my softwoods have been sawn by getting the pith as close to level as possible on the mill.  This does two things from my observations - gets a nice clean heart-centered cant for timber framing, which is much less likely to warp than anything else; and it gets some very pretty cathedral-grained clear boards off the outside slabs of the logs.  If you are truly sawing for grade lumber (FAS or clear) off softwoods, you'd probably want to full-taper saw the log and hope for the best clear face. 

No matter what you do, a heavily tapered log is going to have a significant amount of waste.  Where that comes from is entirely dependent on what you are trying to get out of the log.  I'd prefer to full-taper everything, and get the waste out of the middle - it's going to either be a post, a beam, or firewood.

[bkaimwood]

Amen engineer... Well said, and simplistic

[dgdrls]

http://209.164.108.37/board/index.php?topic=60748.0

good tie in from a post made by @grweldon.

Dan

[4x4American]

That's funny, Dan!  Just about the same question I had.

[taylorsmissbeehaven]

Great post! I read the article last Sunday morning over coffee and went and dug out some good ole tapers and went to work. Not for grade just for my own experience. one must always be learning, Brian