Can you explain this table saw cut?

[Sgian Dubh]

tension can be pretty mental cutting down boards. I've had big oak boards, 12'x200mm that started off straight and flat before it went through the saw and what comes out the other side is bent and twisted and pretty much useless as a long length.

A lot of times it cant be helped given how a tree lays down each layer of growth.Then in the saw mill as its cut green into boards, and kilned with the weight of the multiple boards pressing down it remains relatively straight and flat, til we buy it, where it goes all to hell

Unless of course you happen to own a surface planer

I agree; wood can certainly do funny things sometimes. I've experienced similar distortion after sawing thick oak boards.

Still, I generally avoid and encourage others to avoid specifying tension as a cause of distortion after cutting a piece of wood. The cause of the distortion might be tension release, or release of another form of stress, or stresses for it's often hard to be sure what form of stress was released. As I said in my earlier post I think it's best just to say stress was released leading to distortion: it covers all bases. For instance, if you cut a piece of wood that's case-hardened it will distort significantly, quite possibly lengthwise as well as widthways: case-hardened boards are in tension at the core and the shell is in compression. Slainte.

 

[Doug71]

At least if it happens at the cutting stage there is a good chance you can straighten it up a bit when planing.

Unfortunately wood movement doesn't just happen when sawing and I think it can be worse when you are machining a piece that is finished size and it moves. For example you can have a nice straight piece of Oak for a door jamb, take a rebate out of it and it instantly goes all banana shaped .

All you can really do is use the straightest grain pieces you can find and hope for the best

I always used to say wood movement was caused by the release of tension in the wood but I'm sure @Sgian Dubh will be happy to know his persistence has paid off and I now always refer to the stresses being released

 

[TRITON]

Am trying to avoid having to buy a planer.

Surface planer is pretty much an essential piece of equipment, not just for flattening, but for preparing an edge when jointing boards together. Rutlands one is about 200 quid, which is not a lot really given its usefulness

 

[johnnyb]

After working with the really stable quebec yellow pine your transported to a perfect utopia where your machines suddenly seem perfectly set and the the next job is character oak.... . Arghhhhhgg the stress(definitely not tension!)

 

[Njl]

Surface planer is pretty much an essential piece of equipment, not just for flattening, but for preparing an edge when jointing boards together. Rutlands one is about 200 quid, which is not a lot really given its usefulness

Thanks for the recommendation, I will investigate