Maximum Tenon Width?

[John Adam]

I'm building a small end table for a friend. Dimensions are 8d x 16w x 24l.

Those 8" wide aprons will be joined to the legs with via mortise/tenon. My question is how wide should I make the tenons? I have heard that if I make them too wide, then wood movement might cause issues. I'd rather not do two tenons per apron as this is my first attempt at this kind of joint.....

Any thoughts?

Thanks in advance.

[Sean Hughto]

Make a 6 inch wide tenon in a mortise that is 6 and 3/8ths wide, but only glue the middle three inches. The unglued portions while floating, nevertheless help resist wracking, and strengthen the stability fo the joint.

[John Adam]

Awesome, why didn't I think of that!!!

Thanks!

[Frank Drew]

I'd probably make two tenons, haunched in the middle and at the upper end because one long mortise is weaker than two mortises; although the strength issue is more of a consideration for something like a passage door than a small table, there's still the possibility of the mortise cheeks peeling slightly away from the tenon over time if the mortise is too long.

No matter what, take Sean's advice and leave some room in the mortise for the tenon to expand if it wants to.

[John Adam]

Thanks Frank...stupid question - what's a haunch?

[glenn bradley]

Haunched tenon

[John Adam]

cool...thanks again....man I've got a lot to learn...that's why I'm here!!!

[Frank Drew]

what's a haunch?

John,

A haunch can be any reduction of a portion of the tenon. Google "haunched tenon" for several useful links; this is one, and a couple of the pictures show the double (or twin) tenon I recommended:

http://www.geoffswoodwork.co.uk/mortise01.htm

[John Adam]

Perfect...thanks....