Need some help with grain orientation

[Will Boulware]

I'm wanting to laminate 2 yellow pine 2x12's together to form a thicker board. They've been in my shop for 6 months now, so I think they've had a pretty good chance to move if they wanted to. I've never done a glue up like this before, and I'm wondering how I should orient the pieces to each other. Should the rings form a "circle" like () or should the centers oppose each other like )( ?

Also, can anyone recommend a good book or two on grain orientation in general? I'm new to this whole thing and a good overview of wood movement in relation to joinery would be nice to have.

Thanks,

Will

[James Baker SD]

I would orient them so that the grain along the long edge was all falling (or all rising) when they are glued up. This should make planing them flat a lot easier.

James

[Sean Hughto]

If they are dry and you mill them well, it probably doesn't matter much. That's a lot of glue surface. If I was really concerned about some wort of cupping stresses producing delamination 200 years from now, I might orient them )) so they weren't fighting each other. I'll be interested to see what others think.

[Chris Griggs]

I'm no expert on this, but I'm about to do the same thing so I've been thinking a lot about it lately. My gut says that directions of the rings doesn't matter, and that grain direction on the surface is more important since it will make surface prep easier. Than again, many people say that ring orientation matters when you do edge gluing, but I've never really bought into that either.

However, if it does matter I would think that you'd want to align them the same as Sean suggest )). Or like this )(... My understanding is that when wood cups the rings tend to straighten out. So in theory a )( orientation would cause the pieces to push together at the edges and if they pulled apart it would be on the inside.

That said, I feel I should reiterate, that 1) I really don't know what I'm talking about and 2) It probably doesn't matter.

[John Coloccia]

I'm probably committing sacrilege, but I glue them up whichever way looks the nicest.

[Roy Lindberry]

I'm with you, John. I look to see where the grain will be similar along the joint so as to make it the least noticeable.

That said, Sean's advice about making sure it runs the same direction along the edge makes a lot of sense for planing.

[Frank Drew]

Will,

I've never tested this out in a controlled fashion, but intuitively I lean towards Sean's thinking, having the boards spooning, as it were.

Key thing is using a boatload of clamps; 12-14" handscrews, with their long reach, would be ideal in this application. Of course, if this is just something structural, you could glue and screw and call it done.

[Will Boulware]

Thanks for the replies. I think you've answered my questions here, and definitely given me some points to think about. I hadn't even considered having to plane the edges with two different grain orientations. Love this place!