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Sequence of sawing

Started by appleseedtree, January 17, 2018, 09:04:40 PM

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appleseedtree

Hello Forum. I'm a pro arborist but a rookie sawyer. I've bought an old LT40 non hydraulic and so far just completed one project sawing 5 small locust logs. My current project is on the mill, an 18' x 36" pine log. I've been around it once to trim it up and I've  taken a few 1" boards off of it.   One of the most perplexing things to me is knowing when to saw another board off the top and when to roll the log. It's currently a 25 x 26" cant with rounded corners. I'm looking to get as many 2 x 12s as it will yield. I thought I'd make a couple of 12" wide cants and then make the boards. The top and bottom boards would have lots of wane but I guess I could trim that off. Question is, can I set the two 12" wide cants side by side and saw both of them at the same time or is it better to saw them one at a time?  Not sure if the guides would even allow a 24" cut.
Advice appreciated

ncsawyer

In my experience, when sawing your log down to the desired cant size, you want to end up with a cant that has equal amounts of sap wood on either side of the pith.  The sap wood is stronger than the heart wood, and boards tend to warp "toward" the sap wood or away from the pith, if that makes sense.

So on a 12 inch cant, you would want to mill flitches off of the top of the log until you get down to about 6 inches from the pith, then flip over and mill flitches off of the log until you get down to the 12 inch cant, resulting in a 12 inch cant with about 6 inches of sap wood on both sides of the pith.  This gives you the most stable cant, assuming the pith is centered in the log, and your lumber should stay good and straight.

You mentioned sawing two 12 inch cants from your large log.  This will probably result in splitting the pith or at least yield "lop sided" cants with significantly more sap wood on one side of the pith than the other. In this situation you will probably observe the cants "curling away" from each other as you split your 24 inch cant into two 12 inch cants.  If this happens, all of your 2x12's will have a bow in them.

The best approach, in my opinion, is to cut 2 inch fliches off the sides of the log until you have one 12 inch cant with the pith centered.  Resaw flitches into 2x12s and mill 2x12s from the cant. You will will end up with about the same yield as two 12 inch cants, but much higher quality lumber.
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Magicman

Absolutely and very well described ncsawyer.   smiley_thumbsup

I always determine my target cant before I make the first face opening.  It's kinda like looking at a road map before you leave home because it's good to know where you are going before you leave. 

I will also echo the statement about "never splitting the pith".  It should be centered within the targeted cant.   
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

WV Sawmiller

   Well described by NC and MM. Yes you can often cut multiple cants at the same time when cutting the same thickness lumber but that is usually when cutting something like 2X4s or 2X6s or such.

    You will still get plenty of 2X12s off the side lumber before getting your 12" cant. The total yield will not be significantly different but cutting 2-12" cants and splitting the pith would sure give you lower quality results which you don't want.

   Good luck and welcome to the FF.
Howard Green
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appleseedtree

Wow. Thanks for that. I was really unsure until I read your posts and I'll definitely heed the advice. I figure after sawing a few dozen thousand bf I'll know more!  At this point trying to avoid the big mistakes and get some usable lumber in the process.  And I have to say, between  calling the dealer for tech advice, speaking to friends, and researching the internet including you tube, I always end up at Forestry Forum for the best advice!
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terrifictimbersllc

Agree about taking a 12" cant across the center and sawing that into 12" wide boards.   

Just a slightly different way of saying things in case it is helpful.

Another way to think about your question of how to saw is to produce boards with the figure balanced in the width.  When you look at the grain pattern it is balanced from the center out to each side, the grain pattern is not cut down the middle.

But you'll have a lot of wide boards above and below it so what to do if you want 12" not 24" out of them.  Best performance for the 12" is to take a 12: out of the center of them and leave 6" on either side.  You'll need to decide how bad you want all 12's or fewer better performing ones.

I usually clean up the log like you say(often then putting on a fresh blade) and then cut deep for example 6" x 24 off of either face to leave the 12" cant.  Then come back to the 6x24's and cut a 12 out of the center and then cut this into 2x12s. This limits the wide sawing to 2 wide cuts in clean wood with a fresh blade in what will be the edges of the main 12" cant. 

Cutting wide with no waves is demanding on sharpness of blade. This goes to your question of whether to cut two wide cants side by side. I would never do this with 2 12" cants even if I had two of them on the mill.   Myself I only do this if the two cants are narrow say 6"+ 6", not too tall,  and don't need individual treatment because of having a bit of bow or something else, for example.  Cutting 12's one at a time rather than 24's you can go faster and expect flat cuts with less care.
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

Magicman

Since I do not sell/market lumber my setup is always geared toward the customer's cut list.  I have learned to not be concerned with whether I could have maybe squeezed another board out of the log.  I am better off setting my cant targets based on the cut list.   
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

moodnacreek

All good advice. Trying to keep the heart centered even when it's not there is the thing. On soft, straight or short ,fat pines you may be able to cheat and go faster as you will see.

samandothers

Your questions have been covered.  I just wanted to say welcome!

Magicman

Centering the pith can be quite elusive when sawing off center logs so you have to remember which center is important.  This illustration is what is regularly encountered when sawing SYP.  :)


  
This is a badly off centered log so I turned it so that it was centered horizontally.  The red chalk is for reference for the pictures.  I was illustrating how I determined my target cant.


 
Here I have made my opening face cut and taken two slabs to reach my target.  The slabs will be edged to the cut list.


 
Turned 90° and sawed down to the red line on the right which is my cant target.


 
Again turned 90° and slabs removed to reach my cant target which is then sawed into three 3 5/8" cants.  Notice that the pith is centered within the center cant.  This was not by accident.


 
Turned the final 90° and the "saw through" begins.  Notice what happened to that original off centered pith.   ;D

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

pineywoods

What's not so obvious but very important in Magic's demonstration is yield. I count 21 cuts through the log, for which he gets 36 dimension boards plus 6 slabs which will yield another 8 or 9 boards in as many cuts. approximately 45 pieces in 30 cuts.
Explains why MM has cut over a million board feet and turns out more lumber in a day's sawing than I can in 3 days.
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firefighter ontheside

Welcome Appleseed.  I've been a member a few years, but have only had my mill for a few months.  I have not cut a thing on it yet.  Still getting it set up.
I have several great big yellow pine logs ready to be cut and am happy you asked this question.

Thanks Magicman for the great pictures.  I'm planning to mainly take 6x6's out of my logs, but I will follow your planning and cut process.  I've saved the series of pictures.
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appleseedtree

Magic, so it looks like you've only rolled the log 3 times  and you leave the slabs in place while you saw the next one until you're ready to roll again. That's great to see, as I thought I'd get a reward for the most rolls to get the fewest boards out!  It appears that you are focused on most board feet for the least amount of effort.
Is that actually red chalk or a lumber crayon? 

Magicman

Yes three turns but the slabs were left on each time for picture illustrations.  Lumber crayon.
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

Sixacresand

I have been bit many times by milling a cant down to a desired width, only to have an ugly waves in the cant or bent boards  My policy is to mill cants down to approx 1 inch oversize, mill my boards, then edge, trim off any defects a few boards at a time.  It takes a lot more time and wastes material, but I like straight, uniform lumber.  Customer do not like to hear "turn the hump side up"..
"Sometimes you can make more hay with less equipment if you just use your head."  Tom, Forestry Forum.  Tenth year with a LT40 Woodmizer,

terrifictimbersllc

 I'm guessing Magicman having sawn so many SYP logs like that, knows that this one is  clean and will give it a flat cut the way he is doing it. For example, in the next of the last photo above. I would do the same with a sharp blade on if I knew that that whole side was clean but that's not usually the case for me, I will turn it before I make all those wide cuts and take off the top so that when I make the wide cuts I am cutting into clean wood only. And with a sharp blade.
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

Darrel

Welcome to the forum appleseedtree!  I've learn a whole lot from the folk who have already responded. I've also learned quite a bit the hard way when I didn't follow their advice.  For example, here is why you don't want to split the pith. 

 
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Georgia088

So, MM, you have (3) 3-5/8 cants.  So before you made the two cuts to give you 3-5/8s how large was the cant? 10-7/8s?  I know 3 times 3-5/8ths is 10-7/8ths, but do you allow for the saw blade? for instance an 1/8th per cut? So it would actually need to be 11-1/8?  I'm just curious as to how you figure that.  It never seems to come out exact for me.  It seems wherever I allow for the saw blade it needs to be on the other side lol. 
Thanks!

appleseedtree

Hey Darrel, I love those photos of the long boards. Looks like great boat lumber. Now I really get it. Don't split the pith! And regarding kerf, 1/8" seems to be a generous plenty to my inexperienced eye, I'd like to hear what others figure. And by the way, I've sawed a fair amount on someone else's old Mobile Dimension circle mill and I would figure 3/8" kerf to be on the safe side. You'd lose one board to sawdust for every 3 boards sawed!

LeeB

An 1/8" for kerf is pretty close but really depends on your blade thickness, set and a few other factors. I use an 1/8" and it works fine for me.
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dean herring

MM how do you determine your exact cant target size?
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Magicman

Sorry guys but I got a bit behind while spending a week with Jeff at the Cabin:  LINK

To answer the "starting point" question to reach the target and have all of the cants the same size, this is where Accuset 2 would be very handy.  Since I don't have it, I practiced many times to determine my "starting point" and have these points on my cheat sheet.  The actual numbers would be of little value to anyone else but yes Georgia088, you are on the right track.  Use your figures, try it, and then adjust accordingly.  When you find the "magic" point, write it down.  As LeeB pointed out, my old Setworks allows me to input the blade kerf and mine is not exactly 1/8" but is a decimal.
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

Darrel

So this is what I like about the forestry forum. I didn't even have to ask, in fact I didn't even know that I needed to ask.  But now I know that I should have. I have no setworks other than the rule on my mill and my brain and I know that my cants are a little bit off. I will play with it and figure it out. I'll have to write it down and probably draw a picture of where to stop the head between the lines on the rule. But I can do it.
1992 LT40HD

If I don't pick myself up by my own bootstraps, nobody else will.

Magicman

In your situation I would think that you could measure up from the bottom of the log to determine your targets.
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

Darrel

That's what I do Magicman, but when I get to the last one it would always be a little bit off because I was figuring 1/8" kerf (adding up the thickness of all cants + 1/8 for each). Then when you said that it's a "decimal" something clicked in my little brain and now I know what I need to do. It will probably involve me making my own magnetic scale to put on my mill for when I'm making 3 cants for cutting into 2x4's. But first I have to figure exactly what will work.
1992 LT40HD

If I don't pick myself up by my own bootstraps, nobody else will.

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