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am I getting the most from my logs?

Started by Modat22, July 22, 2007, 10:40:30 PM

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DR_Buck

Quote from: Bibbyman on July 27, 2007, 12:56:27 PM
Quote from: Modat22 on July 27, 2007, 10:28:37 AM
This is what I was originally thinking about on the 14" logs. Note this isn't wood for sale.



I can't figure out the best way to cut this without the waste.


This is the best way to make rocking chair rockers but the worst way to make a usable board.

Tom and Dan have the right idear!

Although not the way I would cut the log either, but why would it warp and twist.  Aren't we looking at quarter sawn grain>
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

logwalker

Yeah, somebody please 'splain that to this country boy. Joe
Let's all be careful out there tomorrow. Lt40hd, 22' Kenworth Flatbed rollback dump, MM45B Mitsubishi trackhoe, Clark5000lb Forklift, Kubota L2850 tractor

Tom

Sometimes you have to saw like this but you should remain aware of where the stresses are going to be.

The 2x6's and 2x4's, in post 25, cut from the side of the log, will try to bend toward the bark giving the piece a lot of "crown".  It is called "crook" or "side bend".  It is a malady that you fight with when quarter sawing.

The 2x6 in the middle of the tree will have the pith and  heart check in it.   It is also composed of imature wood.  Imature wood is made up of the 3 to 5 growth rings first laid down next to the pith. It isn't the most stable, nor the strongest.  Yet, the tension in the board will keep the board straight because there is just as much on one side of the pith as the other and it opposes itself.  You see the stress in a piece like this released when you have to split  the 2x6 later and it crooks.

While I would like to emphasis that there isn't really a right or wrong way, I'll next talk about the way I would treat the log.  It's in the Red and Black figure. (UGA colors  ;D )

The 2x6's on the outside of the log are flat-sawn and will also "bow" toward the bark. The difference is that they will move in a fashion that allows them to be nailed back down or pulled straight.  They will "bow" in the wide dimension. 

The 1x10, the same thing.  It also has the grain centered (heart centered) and the stresses should be equalized on each side of the board helping to keep it straight.   Flat sawn boards are prone to cup so that must be considered too.

By targeting a 6" cant and cutting through and through, all of these 2x6's will retain the opposing stresses that will help to keep them straight such that they won't crown.

When you saw a log and are allowed to produce what the log will bear, you can saw to the grain and make a better product.

When a customer requires that you cut all 2x6's , you fine yourself in a position of being damned if you did and damned if you didn't.  You will create questionable lumber whether you want to or not.

Dan_Shade

I always tell folks that a board wants to bend to where the bark used to be.  this picture I found in the archive is an example of which part of a log wants to move in particular ways.  I attempt to saw so that these stresses end up as manageable.



Woodmizer LT40HDG25 / Stihl 066 alaskan
lots of dull bands and chains

There's a fine line between turning firewood into beautiful things and beautiful things into firewood.

Tom

That is a good picture to show drying shrinkage.  Here is a drawing to help show movement and how it is named.


Bibbyman

I think this diagram is meant to show how wood shrinks at different rates and percents depending on the grain orientation.  Not the same as stress.

Tom beat me to it.  ::)
Wood-Mizer LT40HDE25 Super 25hp 3ph with Command Control and Accuset.
Sawing since '94

DanG

My problem with the diagram is that most of the boards will contain both sapwood and heartwood.  This is likely to produce the rockers that some folks mentioned.  Besides that, Tom's method yeilds more of the desired size, 8 boards vs 7 boards, and yeilds a couple of well sawn wide boards to boot.  ;)  I would still tend to leave a 4x6 or 6x6 in the middle, unless I was real short of logs.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Dan_Shade

My understanding is that the drying differences cause the warping.  Isn't stress more of a problem with a non centered pith?

the other way I try to remember how  board will move is the annular rings want to be straight.
Woodmizer LT40HDG25 / Stihl 066 alaskan
lots of dull bands and chains

There's a fine line between turning firewood into beautiful things and beautiful things into firewood.

DR_Buck

Got thinking about my earlier comment, Tom confirmed what I should have recognized.  The build up of stress from sawing to much off one side.   Rotating and "equalizing" the stress like Ron explained in his earlier post is the best way.
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

Tom

QuoteMy understanding is that the drying differences cause the warping.

Drying will accentuate the movement of the board.  Mostly, it is dependent on the orientation of the grain, but the differences of Sapwood to heartwood, immature wood to mature wood, all will denote the amount of movement.

Growing stresses caused by things like sweep, Reaction wood and crotchs will also cause confounding movement.

Don K

I have discovered for myself sometimes the hard way  ::) what Tom and Dan are illustrating.  When I first started sawing, I sawed from a cutlist for myself. It is disappointing when you saw 108 2X4's with a few extra and dry them and on the big erection day 25 or so are unusable except as bracing and blocking. :(

Being the analytical and perfectionist person I tend to be, I started to study the boards and look at grain and such to decipher why these boards did what they did. Using what I have read on this forum and understanding what wood wants to do most of the time, I stress most of the time, I have learned to semi read a log as I take it apart. You will even learn to read a log before it hits the mill. I am by no means a expert, but I have cut down on my waste.

I am cutting for other people some now and so far they have been satisfied. I have cut them good green lumber and luckily it has stayed that way as it dried. I explain to them that I will try to saw what they want to the best quality I can, but if I see a trait in the log that I think will contradict what they desire I will try to explain it to them.

It is a trial and error thing and you will never stop learning. Heck, some boards will always have a mind of its own no matter what you do.  Keep on sawing and expect some successes and except some disappointments. Also listen to what these different people have to say. There is good knowledge out there and as I have found out, you can learn something from everybody no matter what skill level they possess.

Don
Lucky to own a WM LT40HDD35, blessed to have a wife that encouraged me to buy it.     Now that\'s true love!
Massey Ferguson 1547 FWD with FEL  06 GMC Sierra 2500HD 4X4 Dozer Retriever Husky 359 20\" Bar  Man, life is getting good!

MikeH


Reddog

I think after reading all this, I will just buy my boards and not buy a mill.  :D

Dan_Shade

it's not so difficult, check out this old post, it's where I swiped my previous picture:

https://forestryforum.com/board/index.php?topic=15483.msg221895#msg221895

Woodmizer LT40HDG25 / Stihl 066 alaskan
lots of dull bands and chains

There's a fine line between turning firewood into beautiful things and beautiful things into firewood.

Modat22

Its amazing how many different ways one can cut a log. I've been looking all across the net and its kind of intimidating. I take my hats off to you working sawyers.
remember man that thy are dust.

DanG

Modat, there's two reasons that there are so many ways to cut a log;

1. There are many different kinds of logs.

2. There are many, many different things you can do with them.

You can read and study and talk and listen, and cogitate until the cows come home, but if ya want to be a working sawyer, just put your hat back on and get to work.  Take the log you have and try to make something you want or need out of it.  You'll screw up some logs at first.  Then when you gain some experience, you'll screw up some more logs, but you'll find that you're not screwing them up as bad as you were at first.  After a while you'll look at a log and say, "Hey!  I can get 8 good 2x6's and a pair of 1x10's out of this!" ;)
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

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