Constructing a Round Table Apron

Advice on bending wood in a circle for a round table apron. September 27, 2008

I have to make a round table apron for a 60" diameter dining table. I was thinking of gluing up layers of 1/8" plywood rather than using kerfed lumber. I would then veneer over the ply. Just wondering what others recommend?

Also, is there a standard setback for the apron on a dining table? I was thinking of setting it back about three inches, so the outside diameter would be 54" on the 60" table top.

Forum Responses
(Furniture Making Forum)
From contributor J:
I've bent and laminated 1/8" Baltic birch tighter than that quite easily. However, the basic design idea presents a few problems, I think. One is that a curved apron shifts a lot of stress to the joinery between apron and leg. If you had four legs on a 27" radius apron, each section of apron would be cantilevered out nearly 8", supported by a relatively small area of joinery at each end. Would the apron support the top, or would it be the other way around?

Perhaps more importantly is the question of how many legs to use, which inevitably depends on how many people will sit at the table. A 60" table could easily accommodate six people, unless it has four legs, in which case most of those people would be short of legroom. This is why round pedestal tables are so practical.

From contributor M:
What about 2 -3 layers of 3/8" flexi-ply and then glue 1/8 solid to this after or 1/8" ply? I would keep it back 11/2"-2".

From the original questioner:

I forgot to mention that this is a pedestal table, so the apron is not tied to any legs. The apron is really there to hide the sub plate that attaches the pedestal to the top. The table top is 1 1/4" thick, made of 2 layers of Baltic birch ply, veneered on both sides. I suppose the apron would not really do much structurally but rather be decorative in this application?

From contributor V:
Few layers of rubber plywood, veneer the outside. You could also kerf two pieces of sheetgoods and glue them kerf to kerf, then veneer the bottom edge. If you haven't completed the table yet, you could double the edge thickness to hide the subtop.

From contributor R:
Kerf bending sounds like a stair maker trying his hand at furniture. The preferred way would be laminated strips of wood glued on a form. 1/8" bending ply and veneer would be perfectly acceptable. Don't forget to allow for springback.

A number of plies of similar wood (n) are glued and clamped to a curved form, which is shaped to give the lamination a deflection of "x." When the clamps are removed, the lamination springs away from the form by an amount "y."

Springback can be predicted with the formula y = x/n2. The ratio of springback to the original deflection depends only on the number of laminations. The ratio does not depend on the properties or thickness of the wood or the geometry of the curved form. Thus, for two plies, the springback is one quarter of the initial deflection, or one ninth for three plies and one sixteenth for four plies.

There is no formula for setback of the apron. It's a visual thing and your application is purely decorative.

From contributor V:
I did it using an MDF bending form. I used 1/8+ strips covered by a mahogany strip. I used L brackets to attach it to the table. It was a 5 foot round that extended to 10 foot. Use Weldwood glue and leave it in the clamps at least 24 hours. I usually set back about 4" from the edge.

From contributor N:
Contributor R, why figure for springback if he's going to make a circle? Or are you advocating making it in arc segments, then assembling? I think bending ply with veneer would be the easy way.

From contributor R:
I was assuming he was making a round table with leaves so figured on half circles. Guess I didn't read it close enough. On the other hand the advice holds if someone is doing a round table with leaves.

From contributor N:
Good point. Now I feel silly.