Problem with lumber warping from LT10 sawmill

JandM · June 18, 2013, 02:34:06 PM

I am new to this forum and to owning and operating a sawmill. I am building a sawmill shed with ash trees that have been killed by Emerald Ash Borers. Having some problems with some 20" diameter ash wood warping on my sawmill. Is this sometimes normal with this species? Is there a technique to help this not happen? If warping does happen, should you cut it oversize and go back a shave off some from ecah side to remove the warp.

beenthere · June 18, 2013, 03:36:51 PM

Welcome to the Forestry Forum.
You have come to the right place, and there are plenty here to read and members who have experienced the same problem.
Growth stresses that develop in the growing tree are likely the culprit. Some trees, and some species are worse than others. Balancing the sawing patterns to take off the stressed wood equally on both sides as you saw lumber is the best way to avoid some disastrous results. Think of the tree laying down layers of wood each year that have more tension than the year before. Relieving this tension as you saw will cause the outside boards to bow out, and if not balanced, then the log on the mill will bow the opposite way. A little off each side and boxing the heart pith center will help.
Search on growth stress, and you should find more to read about.

Pull up a stump and sit awhile. More help will be on its way.

OlJarhead · June 18, 2013, 05:58:20 PM

Were the logs stressed? Dried too fast in a very dry climate? Did you straight saw? Quarter saw?

I'm not the expert so won't try to give all the answers as there are MANY great sawyers here that can help but I know more information will be helpful to anyway. So, were the logs straight? Bent? Did you mill to a CANT? Open a face hump up or two the right and flip 180 degrees? Or just take a wack at it and roll it 90 until you could mill away?

POSTON WIDEHEAD · June 18, 2013, 06:54:13 PM

Welcome JandM to the Forum. These guys above me have some good info.

My 2 cents worth is, sometimes no matter how you try to control warping......some logs are gonna be the boss and get the best of you.
Hang in there. Your hard work + The Forest Forum = a very good Sawyer. We are glad to have you here!

drobertson · June 18, 2013, 06:56:37 PM

Jand, welcome, and I have so say I have never cut ash, but all I've read it is, and should be very workable, that size of a log seems like it should behave a lil better, as beenthere suggested, cut and roll, evening the stress as you go, I have seen this in other types, oak, and pine, it could very well be that one log, I have found that one inch off often times helps rather than taking two inches off, david

WDH · June 18, 2013, 07:14:03 PM

Ash can misbehave badly. Flip the cant often once you square it up like BT said. This will help to relieve and even out the growth stress. Even with that, ash can be a challenge.

Jeff · June 18, 2013, 07:45:38 PM

Our west mill had part of the log yard on an old concrete parking area. Occasionally logs would get laid out there to be graded if it was muddy. I've seen ash logs left out in the sun on that concrete quarter themselves over a weekend from stress.

Magicman · June 18, 2013, 08:42:42 PM

Welcome to the Forestry Forum, JandM.

Sawing through from the "hump" or "horn" sides of a log is about the only thing that you can do with most species, and even then the log is always the boss and has a mind of it's own. :-\

drobertson · June 18, 2013, 10:05:30 PM

Quote from: Magicman on June 18, 2013, 08:42:42 PM
Welcome to the Forestry Forum, JandM.

Sawing through from the "hump" or "horn" sides of a log is about the only thing that you can do with most species, and even then the log is always the boss and has a mind of it's own. :-\

+1, this is bout the only way to approach most logs that have any sweep at all, david

rhino135 · June 18, 2013, 10:27:33 PM

I saw a fair amount of ash and I find that there is a lot of stress.
So what I find works, when I square the cant is to keep turning the cant 180 deg after
each cut till the board does lift off the cant anymore.
Hope this helps you out.

Magicman · June 18, 2013, 10:30:54 PM

The fact that an LT10 was used has little to do with what the lumber does.

ladylake · June 19, 2013, 06:06:39 AM

For sure has nothing to do with the mill. If you have a 18" cant and split it into 3 pieces to make 2 x 6 more often than not it will bend some. If you want it straight sawing oversized then straightening it would work but for a mill shed I'd just leave it bowed a bit and put the hump the same way when building. Steve

WoodenHead · June 19, 2013, 06:36:12 AM

I too have had problems with Ash. I find that it is worst when quarter sawing. I've just learned to live with it. Flipping often as others have said helps to relieve the stress. I have also found that letting the logs sit a few months (i.e. don't saw them green) helps a little bit (but only a bit).

WDH · June 19, 2013, 06:58:45 AM

Hackberry gives me fits (sorry Hackberry Jake). Maybe it is the faster grown Southern hackberry. I never split the pith leaving it on one side of the board, but even so, I can get extreme side bend.

One of these boards even has an "s" bend. Spiral grain in hackberry is one cause, for sure. Ash does not have spiral grain, but still has a lot of growth stress.

customsawyer · June 20, 2013, 03:14:54 PM

Ash can be a pain in the ash. ;D

drobertson · June 20, 2013, 08:55:14 PM

I have seen that Danny, and it is quite frustrating to say the least, Just when you think you have the crook figured out it goes the other way again! not much to do, except trim off the crook and accept a narrow board, david

tyb525 · June 20, 2013, 09:26:36 PM

I have had some ash saw great, and others warp the boards to no end. All you can do is turn the cant often, and stack it with weight on it (if you are drying it before building). If you wanted to do extra work you could cut it oversize and then trim it after it dries, but that can be easier said than done, especially with 1x's.