Rabbets for Dining Room Chair Slip Seats*

[Jan Bianchi]

I am about to finally assemble the parts for the eight Madrone dining room chairs I have been making and so have to make a decision. My current 70-year-old dining chairs do not have a rabbet for the seat. The seats sit on top the rails and are attached by screws to angle braces at the corners. Several chair designs have a 1/4-1/2 inch rabbet along the inside of the rails so the seat sits inside the rabbet, and may or may not be additionally supported by angle braces.

As near as I can tell the difference is mainly visual. The first allows the seat to spread out over the top of the rails; and the second more or less contains it within the rails so more of the rail show. Is there a preferred way? If so, what are the considerations?

Also, some chair designs suggest using just 1/4 inch baltic birch for the seat before upholstery, but that seems a little flimsy to me. I don't want th chairs to be as hard a rocks. Should I be moving up to 1/2 inch? If so, should the rabbet be 1/2 deep? Should the rabbet depth be the same thickness as the plywood for the seat?

*I posted this in the Design Forum this morning but no one has responded so I thought I would repost this over here. I hope that's ok.

[Stephen Cherry]

As near as I can tell the difference is mainly visual.

Jan- There are plenty of old chairs with the seat rabbited into, or on top of the rails. It's even OK to wrap the rails.

I would look at chairs on the internet, and see how it was handled in the past for the type of chair you are making and choose the method that best suites your taste and needs.

If the chairs are mostly built, then you need to think about how the seat will affect the sitting height of the chair, and match the seat mounting method to that.

Fine woodworking had some articles on building seats. Also, You want to look very carefully at the foam (if you want foam). I would think about something very dense for the first layer. There is nothing worse than sitting on light foam where your buttocks sinks right down into the plywood. I've thought about using the foam for floor pads for the first layer, with lighter foam over top. Again, this is subjective, and there is no reason to reinvent the wheel. Look at chairs, see how it was done and "borrow" the technique you like best.

Here is an interesting video for an upscale seat:
http://www.pbs.org/woodwrightsshop/video/2600/2611.html

[Jan Bianchi]

That video was interesting. It is the same way my old chairs were made.

I had previously looked at the Fine Woodworking article. He also suggests using sleeping mat foam but only around the edge to keep a sharp definition and avoid the muffin look. He's the one who suggests 1/4 inch plywood. He apparently doesn't use a rabbet but sets the seat on a plywood circle attached inside the rails which seems like a lot of work.