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I have been planing / jointing rough sawn wood recently and edge joining it to create a larger board. Every single time the finished board ends up with a big twist (diagonally opposed corners too low). I need help!

Here are the details: Wood I’m using is redwood (pine). Individual board sizes are 40cm long by 10cm wide and 2.4cm deep. I am edge joining 5 of these using kreg pocket holes and clamps to make a 40 x 50cm board. I’ve noticed the individuals boards have a slight twist and have been able to remove most of this on the planer (jointer). I then feed it through the thicknesser (planer). I obviously get the edges straight and square too. I suspect there is enough twist left in the boards so that it causes the overall board to end up twisted but I can’t work out why the twist would be so subtle in the individual boards and so exaggerated when joined. I use cauls when joining and the wood is left in my house to climatise for a few weeks beforehand.

I’m totally stuck so would appreciate any help!

Thank you.

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    Posting a picture of before & after would be helpful. Also, are you alternating grain direction to help minimize the twisting? i.e. the grain on one board (on the 10cm face) faces up, while the board next to it faces down. – FreeMan Apr 1 at 13:54
  • Yes, show how you plan your glue-up. Pine often requires some care with aligning members with appropriately alternating end-grain to minimize amplifying cupping. In my experience we get to nominal thickness, glue-up taking care to minimize cupping and warping, and then plane to final thickness. To some extent you will always see some warping because the glues are water-based and softwood really soaks it up, changing the geometry of material near the now-unmovable joint. – jdv Apr 1 at 15:39
  • "I suspect there is enough twist left in the boards " If your wood after prep isn't flat, and four-square then that's your problem right there, simple as that. I am confused however that you're getting twist consistently as the law of averages suggest you'd get the right/better orientation at least some of the time. BTW you can ditch the pocket screws! Glue-only edge joints are perfectly sufficient if you do them right, and if you don't do them right the pockets screws can't solve the problem. [contd] – Graphus Apr 1 at 16:53
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    In case you don't know, pocket screws themselves can be a cause of some distortions that wouldn't otherwise occur. If you can stomach the work, you should try doing one panel without using the Kreg jig and see what happens. – Graphus Apr 1 at 16:54
  • Thanks for the replies! I will take some “after” pics to show the twist. I’ll also try doing it without the pocket holes. I hadn’t considered the effect of the glue! Would too much glue worsen the situation? @Freeman - I was told a while ago that alternating grain wasn’t necessary but I’ll put it to the test. – Julian Apr 2 at 7:00
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I'm assuming that you're doing the glue-up right after the milling you describe. It has been worthwhile for me on a few occasions to let the wood rest stickered overnight and mill it again if necessary (it often was necessary, the wood moved overnight.) If you have not let the wood sit so that it might de-stress (twist/cup/bow again) I'd recommend giving that a try.

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