Design Question: Mortise and Tenon

[Chris Wood]

Hey all,

I've got a furniture design question. I'm nearly a total newbie, having made a couple of shelves for a shelfless bookcase I got at an auction (hey, a trade for Mr Lincoln), a pine table for my cats to eat off of (had to get the food above the 6 pound dog).

My plans come from the book _Authentic_Arts_&_Crafts_Furniture_Projects_, subtitled "From the Editors of Popular Woodworking", and the project is the Stickley side table on the front cover (and on pages 56-59). Anyway, the measured drawing has inch-wide tenons on the ends of the (inch-and-a-half) aprons, fitting into mortises on the legs that are an inch and an eighth. Seems a little sloppy, but wood moves, so it ought to be OK. My question is with the alignment: when the top of the apron aligns with the top of the leg, then the top of the tenon will be flush with the top of the mortise, and the bottom of the tenon will be an eighth above the bottom of the mortise. Is that right? Or should I "slide" the mortise up, so the tenon is centered in it?

Chris

[Tom]

Seems a little too loose for my comfort... You may not see the mortise if you center it, but I'd still tighten up the whole shebang... Tom > Chris Wood wrote: [e-mail]

Someday, it'll all be over....

[George]

You want the expansion to occur in the direction where flush doesn't count. Principle is consistent throughout woodworking. You don't want the top lifting off the legs under pressure from expanding aprons.

That said, a 1/8 gap is for 6" or more. For your aprons, a loose fit is much more appropriate.

Anyway, the measured

[Chris Wood]

Ahhh, I get it now. I do want the top of the mortise and top of the tenon to be flush; it makes the top of the legs/aprons always line up, providing a flat surface for the top of the table.

The aprons may expand in width (the tenon is only an inch wide, so 1/8th for expansion is generous.

On the plans, there are panels that runs between the aprons and stretchers below. The grain in the panel will be vertical, so the panel should not change length. Mortises on the legs have an extra 1/8th inch on the "inside", that is, the mortise for the apron has an extra 1/8th on the bottom, and the mortise for the stretcher has an extra 1/8th on the top.

Thanks for the information.

Chris