I have problems cutting old growth pine. I've got a 28" log on the mill. I get down to a 12x12x12 cant. I'm cutting 1x12 boards. I make two cuts and on the third cut my blade dives. I turn it over and make cut and get about 4' it dives. I'll change the blade. Had to go slow to finish. Out of 6 logs I had to change blade 3 times. Logs are clean. I'm running 10 degree blade. Is this going to be the way it is with tight grain pine? Has anybody run into old timber and had problems?
Are you running a lot of soapy water or other stuff to keep pitch buildup to a minimum. Also if the blade is getting too hot you will lose tension and it will dip.
I have cut it on a LT 15 and LT 40. Issues are the same on both mills. I usually had good success though.
By the way, welcome to the forum. ;D
Don
HD,I would try less hook on the band drop down to 7 or even less.Jeez I wish I had some old growth SYP to have problems with.Be sure you have enough set and its even top and bottom slow the feed. Frank C.
I've been cutting some large 16' pine that is partially dried out, cutting 1" just like you are. I've been finding that there is a lot of stress in it, when I get it down to a 12"x12" I can only take a board or maybe two from a face and then have to take some from the opposing face. Even the straight grained pretty looking logs have a lot of stress and they will just curl right up if you take to much from one face of the cant but if you keep an eye on things and take the log down equally no problems. Just a thought maybe that is what your dealing with?
those same sap on the blade problems have plagued me when sawing fresh post oak. the real problem is when the bade is sapped up on the outside since my lube only goes on the inside. pc
HD, chances are you are sawing a butt cut and sawing from the butt end. Compression wood is simple wood that has been mashed and buckled by the weight of the tree. When trees are felled leaving a low stump, that bad wood ends up in the log.
Butt logs are best sawed from the small end. Be sure that there is no pitch buildup on your blade. I use 2oz of Cascade per gallon of water for lube and increase the flow on bad logs. I use 10° blades, and I understand that 7° might be better, but I haven't decided to change just yet. I saw approximately 75Mbf of SYP each year and do OK with the 10° blades. The great majority is large old growth. Matter of fact, that's what I sawed last week and beginning tomorrow what I'll be sawing this week. Some 30"+ SYP logs.
Proper blade alignment is an obvious requirement.
Quote from: Magicman on September 28, 2010, 09:04:08 AM
Compression wood is simple wood that has been mashed and buckled by the weight of the tree. When trees are felled leaving a low stump, that bad wood ends up in the log.
Thats the good wood!! haha , I love a big old flared out bent over tree with some good compression wood when I look at it I see $$. A big limb can have some nice area of figured compression wood too.
Thanks for the replies. You know it just might be the wood. It just blows my mind to get pretty cuts and then the blade dives. I'm useing half bottle of pinesol in 5 gallans of water. The blade is clean. I guess if i keep having problems i'll try changing set and degree on blade. I haven't run into this problem before. I've cheked alinment and all looks ok.
I'd also check the blades coming off and be sure that the set has not somehow been knocked out. I cut quite a bit of old growth pine, recycled beams, jump butted pitch trees and sinkers using 10° blades...tried the 7's and switched back. A dash of diesel will cut that pitch on the blade.
Quote from: northwoods1 on September 28, 2010, 10:04:43 AMThats the good wood!! haha , I love a big old flared out bent over tree with some good compression wood when I look at it I see $$. A big limb can have some nice area of figured compression wood too.
Yes, I understand, but you are not talking about SYP either. Folks aren't looking for figured wood with SYP, they are looking for stability.
Quote from: Magicman on September 28, 2010, 09:04:08 AM
...... Compression wood is simple wood that has been mashed and buckled by the weight of the tree. .........
Not exactly a good description of compression wood. :)
Compression failure in wood is "mashed and buckled". Trees tossed around in storms often show compression failure. Marked reduction in strength as the wood cells are crushed.
On the other hand, compression wood is abnormal wood that has developed usually on the compression side of the tree (lean side, or underside of limbs). The compression wood has wood cells with walls of high fibril angle. These slanting fibers shrink in the longitudinal direction much more that regular (normal) cells thus causing warp when the wood cells dry.
A thin cross-section of wood held over a light will show the areas that are compression wood as very dark (no light passing through) as a result of the high fibril angle.
Here is some good reading on the compression wood, and also discusses how it affects wood strength.
http://www.metriguard.com/fiber.htm
I talked to an old sawyer about this. He has run into the same problem. His solution: He adds 1/8 cup of Dawn dish soap to his lube, and then sprays WD-40 on the blade about every other cut.
Quote from: paul case on September 28, 2010, 08:36:18 AM
those same sap on the blade problems have plagued me when sawing fresh post oak. the real problem is when the bade is sapped up on the outside since my lube only goes on the inside. pc
I have run into sap buildup on the non-lubed side of the band when sawing old pine beams. I added additional diesel wipes top & bottom and on both sides of the cut. It keeps the blade very clean.
I'd try blades with more set first. Steve
OK, My blades are clean on both sides so I don't think it's a lube problem. I guess i'll stick with the 10 degree...
Ladylake, how much more set?
What's happening with the tension when the bad cuts start?
Thanks for the info about SYP. I have a few butt cuts, that have given me trouble....
This just fits.
Nate
Thanks beenthere for a more descriptive definition of "compression wood". Yes, a tree is very heavy and the effects of that weight does strange things, especially with SYP. (I didn't find a definition in the FF dictionary.)
I was questioned in a PM concerning sawing from the "little" end.
My absolute preference is small end first, on everything. With big logs though, you have to carry the head to the far end, lower it to the sawing height, and then back up to log to be sure that the head will clear the log.
Logs are easier to set up because you are raising the toe board closest to you. Less walking.
When sawing knotty logs, the blade doesn't tend to follow the limb and raise up. You are sawing into the crotch. Much less tendency for "knot wave".
You can only saw as much lumber as the small end will yield, so it's much easier to determine where to make your opening face when you are looking at it.
When sawing butt cuts with the potential for having compression wood, you have sawed through "good" wood and your blade is on track before it hits the compression. You may loose 6" or so, but at least your blade doesn't have to climb out or adjust itself in good wood.
I'm sure that other sawyers will have their own preferences, or add items that I didn't think about. There are just sooo many variables when setting up and sawing logs. Each log is really and individual unto itself.
My experience and preferences mostly match what magic said in the previous post. Last week I sawed about a dozen good sized syp logs that added some new experiences. most were 14 to 20 inches on the small end, nice straight logs will little taper. Some butt cuts, some second cuts, all 12 ft long. I've cut a lot of syp over the last 10 years, but I have never seen any log of any species that wiggled and moved as much as these did. Some of the cants visibly twisted, just about every board warped like crazy as soon as it was cut loose from the cant. The logs all came from trees that had been completely ripped out of the ground by a tornado. That may not have had anything to do with it, but they were about like trying to saw a wet noodle.
An interesting thing about how trees grow is the effect of the growth hormone auxin. Auxin stimulates cell growth and is produced in the crown of the tree in the growing buds. The auxin moves down the stem via the inner bark (phloem) and is distributed evenly around the bole of the tree. This auxin stimulates cambium growth during the growing season when the active buds are producing auxin. Light breaks down auxin over time, however, and if the tree is bent over from vertical, the auxin that accumulates on the underside of the lean is more protected from light and the higher concentration of auxin stimulates the cells in the cambium on the underside to grow faster than the cambium cells on the upper side of the lean. As Beenthere points out, these cells that are stimulated to grow have different make-up than normal cells in that the microfibril angle of the cellulose molecules that make up the cell walls is different and the cell walls contain more lignin (the glue that sort of fills in around the cellulose chains to form the solid cell wall). The effect of the faster growth on the underside of the lean (the bottom is growing faster than the top due to the effect of the higher auxin concentration on the bottom) actually straightens the tree back up to the vertical over time leaving a curve that we call sweep. A log with sweep always has compression wood on one side. When the vertical point is again reached, light affects the auxin the same all the way around the bole again, and even growth occurs from that point and on up the straightened point of the the stem.
That is way more information than anyone wants or needs. Suffice it to say that a tree that is bent over will try to straighten back up in response to light :). Whew, I got that out of my system ::). And if any of y'all understand all that, then you must be a little weird too :-\.
Well, i didn't have problems cutting until I got to the center of the logs. My problem isn't boards twisting after a cut, its just moving along fine and then the blade dives. I can change blade and its fine until I start the next log cant.
Magicman, my logs are set up both small and butt ends on ground. I don't have a way to move them now that there next to the mill.
Correct me if I'm wrong, Softwoods more set,Hardwoods less set. Is this right YEE SEASONED SAWYERS???
gymnosperms -> softwoods -> compression wood on lower side
angiosperms -> hardwoods -> tension wood on upper side
One other item about sawing logs with sweep. Orientate the log so that after the faces are opened, you are sawing the cant from either the horn or hump side. That way, you eliminate the heavy crowning that you will experience if you saw it from the side. You probably will still have to flip the cant as boards are removed and stress is relieved.
Twisted trees/logs are going to give you misery anyway. Beetle killed logs that have dried somewhat seem to move less than fresh cut SYP. I'll be back to sawing beetle killed logs tomorrow.
Yes more set for softwood maybe aroud 28 thousands, the dryer the log the worse it is. Steve
Here is a prime example of sawing a butt log with sweep. I prefer to lay them on the side with the "horns" toward the clamp for the first face opening.
(https://forestryforum.com/gallery/albums/userpics/20011/2410/DSCN1089.JPG)
Notice that the pith is not centered in the log on the butt end.
For the second face opening, I rotate 90° and saw the horns off.
(https://forestryforum.com/gallery/albums/userpics/20011/2410/DSCN1091.JPG)
The log is then rotated and the other side face is opened. The last 90° rotation has the hump up. I then saw through.
Notice that the cant has raised up off of the saw deck as boards were removed. I should have rotated this one sooner. :-\ It must now be rotated 180° and boards removed from the other side of the cant. The old folks called this "suck butt". :D
(https://forestryforum.com/gallery/albums/userpics/20011/2410/DSCN1087.JPG)
Here is an example of the band following the stresses of compression wood in the butt.
(https://forestryforum.com/gallery/albums/userpics/20011/2410/DSCN1086.JPG)
I would prefer that the log not be cut so low to the ground. Leave this junk on the stump.
It is interesting that Foresters rail about high stumps to loggers. They want the stumps cut as low as possible to reduce site prep costs. Then, the mills rail about the flared butts and how they mess up the computer scanners that determine the sawing solution if the loggers cuts the stumps low. Then the band millers don't like the wood at the butt of the tree because of how it saws.
Nobody likes big butts but the Foresters :D.
And the landowners if they are selling by weight. Butts weight too. ;) :)
I have a band mill and boy can relate to the problems mentioned - I also like to saw with the little end up at the head. I never knew why the blade would dive about 6 ~ 8 from the end of the cut. After several attempts, I gave up on SYP. Only because I never could get it right. I have a buddy who also runs a band mill and claims he can saw SYP - so I broke down and bought some from him. Needless to say the boards looked l sawed them :D and it made me feel a lot better...
My opinion here... so no flames please - I think SYP is best sawed on a circular mill. I say this only because I also have a few buddies that run circular mills and they can cut some of the best SYP you've put a eye on... I refer all the SYP calls I get to them.
Quote from: Magicman on September 29, 2010, 10:00:28 PM
Here is an example of the band following the stresses of compression wood in the butt.
(https://forestryforum.com/gallery/albums/userpics/20011/2410/DSCN1086.JPG)
I would prefer that the log not be cut so low to the ground. Leave this junk on the stump.
when i first started i encountered this problem with some small post oaks . i thought it might be my blade sharpening but i noticed it still did this on some logs even with a new blade. i am glad you posted this,because i didnt know. thanks pc
Danny are you trying to overload my low brain power. ;D Well it worked if that was the game plan.
There is some wood that will give trouble no matter which end you try to saw from. In the explanation that was given that the blade cut fine then started to dive I would lean toward heat in the the blade which will lower blade tension since he said that the blade was sap free.
Hey dad, I wish you lived close to me. I love to saw SYP. I like it better than hardwood. ;D
Don
I think SYP saws like $$$. ;) :) :D
magic,
you know the easiest and most sure way to double your$ is to fold them in half and put them back in your pocket!!! pc
Magicman, thanks for the pictures. I think u always say (if you don't take a picture it didn't happen, or something like that).What set are you useing? Ladylake said to use around 28.
Cutomsawyer. If the blade is heating up would u say that was a lube problem? I have no build up or belt slipping marks on the blade.
I took a few blades to my shapener guy and he going to put 28 set on a few blades and then I'm going to try that on these logs. I have around 2 doz logs to finish. However...
I think I have had a mistake with the mill. I just could't believe it was the blade so I started looking at the mill adjusments. I never had to adjust much on the mill so it new to me. I made minor adjustments according to my manual. Now I think i have things out of wack with it. I been on phone with manufacter for last two days and still having problems. Still doing the diving thing. I should have waited until I got back blades with diff. set on them and try that first. I got to many irons in the fire so I was trying to rush things. Deer (bow)season started and i wanted to go yesterday but wanted to get log problems solved. Can't sleep very good cause it bothers me that I'm having problems with the mill. It's the main thing that is on my mind and want to get it solved and move on to other things. Thanks for the replies and interesting comments.
I run 1/4" down pressure with the guide wheels. If your running less than that give that a try. Steve
HD, I use 10° blades and send them to WM for ReSharp.
If the blade is heating up it can be caused by a few different things one is to little lube but if that is the case you should also see some sap build up so I would lean towards the shape of the gullet of the blade in that it is filling up and the sawdust is over flowing in to the next gullet and it just gets worse and worse the longer the cut is. The sawdust flowing over your tooth will fill up the kerf that in turn will make the blades get warm to the touch as there is no clearance. When you finish a cut turn the mill off and see if the blade is warm to the point that you can't keep your hand on it.