Dining Table design - Joints and overall design

[andrew whicker]

Hi all,

I am making a dining table that will fit 8 people comfortably and probably 10 people if you don't mind feeling cramped. The top dimensions are 96 inches x 40 inches x 2 inches thick

The legs (I'm planning) have the dimensions shown below. I'm curious of your thoughts from whatever angle you'd like to review. However, I think one of my biggest concerns are the joints between the vertical legs and the horizontal parts of the legs. I want to be sure they are strong enough AND the wood movement won't be a problem. I'm not planning on pinning, just gluing as bridle joints. Maybe the vertical legs should be males instead of females (make sense, now that I think about it)?

The leg pieces (as I'm visualizing) will be made from three pieces, each 3/4" thick, glued together (2 1/4" total). Maybe just better to buy some 10/4's and make them out of one. I'm not sure. The original idea was that I wouldn't need to use a dado blade or router to make the bridle joints if I made all the layered pieces the same thickness, plus it might have a neat visual effect. I could shoulder plane as needed to get the male tenon the right size. See photos below. I have only drawn the female so far.

The vertical legs would have grain going up. The horizontal pieces would have grain going along table length. That's probably obvious, I guess.

Plan was to cut the radii on a bandsaw and orbital sand it down.

Any and all thoughts welcome.

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[Dave Richards]

I think you'll have a problem if you try to make the corner as part of the vertical section of the leg. I think it would be better to make the left from three pieces with the grain running generally diagonally in the corner piece.

[Robert Cherry]

I built a coffee table years ago with a similar design leg. I suspect at dining table height you may get enough wracking that the table could feel wobbly. Perhaps add some lower stretchers to stiffen it up?

Your table should seat 8 adults comfortably at that size. 24” per person is a good allowance plus 12” for the person on the end.

[Yonak Hawkins]

Aprons are an age-old part of table design for a reason. They're not just for looks.

On the other hand, if you add some meat to the legs and more extensive joints you may get the stability you need for such a large table..

[andrew whicker]

I'm not understanding the why. Could you explain? This would certainly making buying wood cheaper.

[Dave Richards]

With your design you end up with short cross grain right where you need strength at the end of the curve.

[Jamie Buxton]

Here's a dining table I built a couple years ago. It is very similar to yours, except that my base is upsidedown from yours. I say that the stresses and potential wobbliness are essentially the same. I can also tell you that mine is nice and stable. I think yours will be okay too.

Mine is 118" by 40" with leaves hanging on the ends. (That's the state you see in the pic.) The legs are sapele, with cross section of 3" by 1.75". My joint at the elbow is simple mortise and tenon. A good bridle joint should be even stronger. Not that it matters for this discussion, but the top is sawn veneer of plainsawn sapele.

diningtablewithleavessmall.jpg

[andrew whicker]

I see it now, thanks. Would pinning be an option in lieu of your recommendation?

[andrew whicker]

How did you attach the legs to the top?

[andrew whicker]

I'm not understanding the racking concern. Racking, from what I can tell, occurs when you have pieces that come together at joint and loosen over time. Each pair of legs in this design is a solid piece. I hope to use a lap in the middle where they come together. Furthermore, everything will be attached to a 2" thick table top. Each leg is 3" along the long axis of the table and 2.25" wide.

I'm also wanting to splay the legs out a bit to add to the look (angle outward), which would shorten the horizontal pieces and add some stability. I'm just trying to make sure I'm only getting myself 25% over my head, not 100% over my head before I make the move.

Is racking really a concern?

[Jamie Buxton]

How did you attach the legs to the top?

Nothing fancy. The top needs to separate from the base for transport, so the connection is screws not glue. I glued more sapele on the top of each leg so I had three layers of the 8/4 for the top 1 1/2" of the leg. Screws go up through the sistered-on pieces into the top. The screws are 1/4-20 connector bolts, and they screw into brass threaded inserts in the top.

[Wayne Lomman]

I'm not confident about the curved joints. The legs aren't much heavier than chair legs so not much to work with to counter the short grain no matter which way you do the joint. Try making each leg as a one piece curved laminated beam using 4-5mm thick timber. This is the only way I can think of to get the strength into the design other than a steel frame covered in timber. This will be a heavy table. It needs good engineering to sustain itself plus the loads imposed by 8-10 people. Cheers

[David Utterback]

A spline or similar combination of mixed grain directions in the curved joint would work in some instances. Even better if it extends into the rectilinear portions of the base like a Greene and Greene ebony spline.

[andrew whicker]

Hmm... okay. I'll keep pondering. I need to make a move soon. I can cut the leg widths 'wider' in the sense of 4" instead 3". The other width would still be 2.25" or the thickness of three pieces of wood laminated together.

Time to draw a new plan up and see what you guys think!

Thanks and cheers,