Drying Twisted Wood And Knowing When To Walk Away
When I started cutting lumber for myself, I thought I could do it better than Home Depot. No more twisted and crooked lumber for this guy. I was gonna be the guy that did it right, the one that wasn’t affected by the limitations of mass output, the one that made sure every step was followed, and the one that made sure that every board behaved. I thought that if I properly placed my sticks and used more sticks and weighted down the pile and otherwise paid attention, that the lumber would respond in kind. Boy, was I wrong.
One of my favorite stories to tell people is from my early milling days when I tried to dry some sweet gum. The customer wanted to make flooring out of the tree, so I milled the log into 4″ wide boards. I took that nice-looking, 4″-wide sweet gum and stickered it on the bottom of a stack of lumber the was as tall as the Bobcat could reach. There must have been at least 3,000 bd. ft. and about a billion pounds on top of that sweet gum to help keep the notoriously ornery lumber flat as it dried.
After a few months on sticks, the lumber had twisted in unimaginable ways. Some of the boards twisted 45 degrees. Somehow, they pushed up the entire stack as they dried and went on their merry way getting all crooked without regard to my perfectly placed stickers and extra weight. It was really incredible. Even if I showed you a dried board in person, you may not have believed it. I had to cut some of the wood as short as 8″ long, just so I could straighten it on the jointer before it went through the planer. I don’t cut sweetgum anymore.
After my sweetgum “education”, it was clear that some wood is just not going to dry straight. Certain species always dry wonky. Flatsawn sycamore, elm and cottonwood all come to mind, along with the sweetgum, as bad actors. If quartersawn, they are all more stable, but if flatsawn, all bets are off. I always say that flatsawn sycamore dries like a potato chip. Elm and cottonwood dry more like thinly sliced potatoes that are fried in oil.
And, it isn’t just certain species that twist. Branches or trees that grew with a lean will dry crooked, even if they came from normally cooperative species. Certain areas within the good lumber can dry crooked too. Wood around a branch or crotch always dries spastic because the grain of the wood is flowing in many different directions. And, the lumber can still dry crooked if the lumber isn’t cut with the pith of the tree down the center of the board. There are just too many forces in the world trying to make the lumber unstraight.
The last one, and the one that I cannot defeat, is the tree with a twist. Not twisted lumber, but a twisted tree. The twist gets in the tree as it grows, and it twists the lumber as it dries. I have seen it in may different hardwood trees and the resulting lumber is always twisted. This past summer, I took a photo of a dead sycamore that showed off this “death-twist”, which would make an already cantankerous lumber throw an off-the-charts fit. It is easily identified by looking at the surface checks in this dried out log.
Click on any photo to enlarge.
Sycamore doesn’t always look like this. The grain is normally wavy, which makes the lumber dry unflat, but it isn’t usually twisted. This tree is very, very twisted and will dry with a pronounced twist in every board. It is best left as a decoration in the field. The good news is that this twist is usually obvious, even when the bark is on the tree. The bark will have the same twisted lines as the log, and let you know that it isn’t worth milling.
In the world of sawmilling, however, very few logs come right out and announce that they are going to twist. They don’t say, “Don’t waste your time cutting me, idiot!” Many logs and pieces of lumber look good but end up doing what they want, and you have to accept that some lumber just won’t dry flat. I still do everything I can to make the lumber dry straight, but I know now that crooked lumber is part of life and, in the meantime, I have become really good friends with my jointer.
Thank you again. My wood GOD
They say I should reply to all of my comments, but I don’t know what to say to that one. Your welcome?
Hi Scott, There’s a monograph by Ferdinand Cohn, written in German about a hundred years ago that describes torsion in trees. In your experence, do they tend to torque in any certain direction? The sycamore you show has a right-had twist, that is, if you ran your right-hand fingers along the cracks, your hand would travel in the direction of your (also right-hand) thumb. Does this indicate some “right-handedness” in nature? Or is it like with people, some percentage, say 15% are left-handed? I’ve wondered about this a long time.
I have never paid attention to the direction of the twist. In a quick, informal survey of slightly twisty logs at my shop, one went to the left and one went to the right. I thought that it would matter which end of the log I was looking at, but it doesn’t. If it goes to the right, it goes to the right, no matter which end you look at.