Yes, the boards will move how they want. The cool part is that this movement is predictable. This is why we alternate the grain. Not to mitigate movement, but rather work with it. By not alternating the grain you are facing all of the cupping movement in one direction, the result is what we see in this post. Yes, by alternating the grain direction you end up with an "S" shape, but not nearly as drastic as you make it out. The subtle cupping in alternating directions ultimately results an a relatively flat surface, mitigating the direction of movement rather than compounding it. No, it's not a meme, it's centuries old knowledge. But I'm sure you know better than the hundreds of previous generations of woodworkers.
That said, you are mistaken. I mean, yeah, folks have known wood works this way for ages. But that's not all that relevant to "proper" furniture making. The idea that you need to do this on every glue up is very much just conventional wisdom / meme stuff.
When you're building a table top, the goal is not to build a table that 'warps nicely'. It's to build a table top that doesn't warp. Sure, a subtle cup is better than a dramatic one. But it's still not an acceptable result. You can't sell a 'relatively flat' table.
You do not account for wood movement by alternating grain. It is too late at that point. You do it by milling the boards so that they won't cup. (Or buying stock that was milled that way.)
Op's problem is not that they oriented the boards wrong. It's that they bought the wrong boards.
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u/Bigdaddyblackdick 5d ago
I’m still a beginner but don’t you want the grain to alternate specifically for this reason? Someone please correct me if I’m wrong