How to rip long planks without causing them to deform?

Question

I may want to rip down a stain-grade pine 1x5 plank to about 3-3/4 width. I have a number of these planks that have been sitting indoors for over a month so any movement should have settled already. I'm making door jambs so I need these to be straight. I could take a plank, straighten one edge with a power planer, then run it through my table saw but I'm concerned that it will crook after it is cut and if not immediately then possibly way down the road after it's been installed.

How can I narrow down a plank without it becoming crooked or otherwise deformed? Alternatively, would I be better off taking a 1x4 and gluing on a narrow strip to make it wider?

Answer 1

Any piece of wood could warp at any time between now and x time in the future. If you wait to use it until you think the wood won't warp on you, then you should probably find a different hobby/profession to fill your time because you're going to be waiting a long time.

The drier the wood is the less likely it is to warp. Get yourself a moisture meter and look up info on what the idea moisture level is for your pine. Wait until the wood is that dry to minimize the likelihood of it warping.

On the other hand, since the wood has been sitting inside (presumably in the same indoor atmosphere where it will be installed - inside my garage is different than inside my house, for example), it's probably dry enough and you shouldn't worry about it. For example, I live in a house built in the 1890s. I've got wide pine trim in many parts of it, and none of it seems to have warped in over 100 years.

Your level of worry is entirely up to you, but I'm guessing you have nothing significant to worry about at this point. You might have to replace the wood, but it's likely that if it twists when you cut it, no amount of further drying would have prevented it.

Answer 2

There are 2 things that cause wood to 'warp or kink' after it's cut. This is caused by stresses on the wood, sometimes if the wood is dried really fast and unevenly, there can be stresses added and by cutting it (especially the long way) you are releasing this stress, at least on one side, and will usually bend the opposite way, Planning an edge can even release some of this, if it is there.

The other is naturally stressed wood, usually from a leaning tree or branch, and it can become pretty stable, until you cut it, if this is the case there is nothing you can do but make curved furniture...

Pine generally isn't affected by the 2nd issue and the first I think most manufactures don't make that mistake any more. So the only thing left is natural moisture movement, which you have little control over and clear straight grained wood generally is pretty stable once it dries and you should have little worry.

On top of that pine tends to either warp and twist right away, or not at all. and it's soft enough that once it's nailed down, it almost never moves, other than the swelling and shrinking of the seasons.

Answer 3

Your approach makes sense, but if you're particularly concerned about this wood, I suggest you remove the extra width in two cuts, rather than one. Joint one edge straight as you suggest, then rip down to within 1/4" or so of your desired width, let the wood settle for a day or two, then if the wood remains straight, rip to final width. If not rejoint and rip to final dimension. That shouldn't be necessary for properly dried, reasonably straight-grained pine, but it will take care of any problems that do arise.

As others have said, if dry at installation, pine isn't going to move much at all, beyond normal expansion and contraction, once it's fastened in place.