Designing and Building a Through-Leg Table

Question

A popular, modern style of table has the legs going through the table top, so that the end grain of the leg is exposed. Of course, the problem with this design immediately becomes the expansion and contraction of the table top, which would push and pull against the legs. An example of this style is the "Big Sur" dining table at Crate and Barrel. Other manufacturers make similar looking tables, which is apparently a variation of a "Parsons table" design. I've found one other discussion of the style on the web, and people were convinced manufacturers were using cleverly disguised plywood. I have seen the Big Sur table in person, and I can tell you with complete certainty that the tabletop is solid wood.

Looking under the table, there are kerfs approximately 5 inches apart, which I assume are to allow for expansion. The bottom of the tabletop is reinforced with metal brackets screwed into place. I assume this is to strengthen the tabletop due to the weakness introduced by the kerfs. The kerfs do not go all the way through the tabletop, so I assume expansion would still be a problem. Additionally, there is a 1/8" gap between the table top and the legs, which I assume is there to allow for additional expansion, but would probably also harbor food crumbs.

I have never heard of kerfing the bottom of a tabletop before. Is this a thing? Am I interpreting the design correctly? My wife and I, who rarely agree on anything, both like the aesthetics of the table. I've talked about custom building one but I'm having second thoughts. Is the table stable or is it just a bad design?

Answer 1

Make the top from carefully selected quartersawn stock in a species known for low movement and you can go ahead with a table like this and not worry greatly about expansion and contraction.

There's a fairly simple (and much cheaper!) alternative and that is to have the short rails float or be an easy sliding fit in the mortises on the legs. The top would still be attached to these rails in a conventional manner but it leaves the front and rear leg assemblies free to move in and out as needed through the seasons.

I have never heard of kerfing the bottom of a tabletop before. Is this a thing?

Apparently! I am not at all convinced it would do enough to account for movement in any location subject to wide swings in humidity*. However many modern American homes with central air etc. have much smaller humidity changes, and some present-day furniture actually takes advantage of the fact as mentioned in a couple of previous Answers.

Is the table stable or is it just a bad design?

I think this is a stupid design for a large dining table and, apologies, pretty ugly to boot. But the price they're charging for this big ol' hunk of rustic, that's just insane o_O

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*Especially since they don't run the full length of the table.

Answer 2

Here's another option: put the top on while it's wet and swelled. I use "wet" in relative terms.. it just needs to be at or near maximum expansion. That way it only moves in one direction relative to those legs.

But i have to agree with the last two sentences in Graphus's response...