design question with movement in mind

[Brad Wood]

Hi,

I'm getting ready to do a dining table. First project of significant size. Most of the stuff I do has been small and movement/expansion hasn't been an issue for me.

The table top will be a basic cutting board style lamination. I've done a rough mock up in Sketchup so you can see how I intend to wrap the perimeter with some trim (for lack of a better term, someone might know the right term for me?).

Anyway, I got to thinking about movement last night as I was going to sleep. Do you suppose I should do what I think is called a bread board style end on this to allow for wood movement? will I run into issues with that mitered joint in the corner?

thanks

ps - please pardon the lack of skillz when it comes to Sketchup

[Howard Acheson]

With solid wood, you can not have the type of trim surround you picture. It would restrict the natural seasonal expansion/contraction of the main panel. You would need to use a breadboard type of attachment on the trim against the panel end grain. Because the long grain trim would be glued to the center panel, it too would expand/contract as the main panel moved. Therefore, miter joints can not be used.

[Brad Wood]

Thanks Howard, once I started thinking beyond the sketches, I realized this might be an issue.
Sounds like my best bet would be to put bread board ends on and not do the side trim at all.
If I did the trim like in this new picture, it seems like I would still have expansion issues with the table possibly growing wider than the end?

[Ralph Barhorst]

It seems like I would still have expansion issues with the table possibly growing wider than the end?

You are right, this still will be a problem. But it can be resolved. Attach the bread board end using a tongue and groove joint and use dowels to hold the end with glue only on the front few inches. The dowels would enter from the bottom and not go through the top. the dowels holes that are near the center and rear would be elongated to allow for the expansion.

[Jason Beam]

Even with breadboard ends, that's the case - some parts of the year they'll (the end and the panel) be exactly the same width. Other parts of the year the end will be slightly longer, and still other parts of the year the panel will be wider.

This variation depends on the width of the panel, species, grain orientation, initial moisture content when built, relative humidity variations, the alignment of the planets, whether its a leap year, phases of the moon and if your mother in law will be visiting.

Crazy huh?

It's one of those things you just accept with such a design. There's really no fighting the wood, it'll move whether you like it or not. So you can plan for it by adding some details that might hide the misalignment some. For example, a very small chamfer at the seam line (even just on the ends) can visually hide the size differences. Another idea is to turn that misalignment into an exaggerated design element by making your ends 1/4" or so longer on each end then style 'em up a bit with a chamfer, round over, or what have you.

[Chris Tsutsui]

My friend made a solid soft knotty pine table with a similar design you pictured. The resulting top changed IMMENSELY in dimensions. He ditched the solid pine top and tried a thin tongue/groove panels as the top over MDF. Then hardwood pine as the border.

This was more stable since the T&G allowed panel movement, though the pine still moved so much that there's still cracking going on.

Just shows how difficult it can be.

Keep in mind that the orientation of the hardwood board grain. You want to alternate the boards so they all don't cup or bow the same way.

[Rod Sheridan]

Brad, I normally leave the glued up top with the end grain showing.

No expansion issues............Rod.

[Jim Kountz]

Brad, I normally leave the glued up top with the end grain showing.

No expansion issues............Rod.

Yeah what he said.

[Howard Acheson]

Brad, as Rod suggested the best way to deal with the issue is to NOT use a breadboard end. Don't use anything. Breadboard ends can look really strange when you use a wood like oak that has lots of range of movement.

IMO, breadboard ends should be reserved for colonial or farm style furniture.

[Brad Wood]

Brad, I normally leave the glued up top with the end grain showing.
No expansion issues............Rod.

Yeah what he said.

Brad, as Rod suggested the best way to deal with the issue is to NOT use a breadboard end. Don't use anything. Breadboard ends can look really strange when you use a wood like oak that has lots of range of movement.

IMO, breadboard ends should be reserved for colonial or farm style furniture.

While I appreciate the input from previous folks.. these last three seem to be the most appealing. Now I just need to talk to the "boss" about my design change. (she doesn't have to worry about stuff like this... she just says "I want it to look like xxx")

[David DeCristoforo]

You might want to consider a "floating" edge detail like this:

bd_edge1.jpg

The exact profile is not critical (nor is the 2" dimension). But you can miter this edge around a solid wood top without breaking any rules!

[Jules Dominguez]

Clever idea, David. Haven't seen that before. Have you actually built one like that?
Brad, exposed end grain doesn't look bad if properly finished - sand to a higher smoothness and pre-wet it with solvent so it doesn't soak up too much oil or stain and come out a darker color than the long grain. It can add to the visual interest of the piece. It's a matter of personal taste, though. Try it on a sample.

[David DeCristoforo]

"Have you actually built one like that?"

http://www.daviddecristoforo.com/chessdd/tables.html

[Jules Dominguez]

Thanks, David. That's beautiful work. I assume the relative "wideness" of the edging is to provide strength at the corners?

[David DeCristoforo]

"I assume the relative "wideness" of the edging is to provide strength at the corners?"

Well... not really. I just like the look. The edge can be whatever you like