What size tenons for a dining table

[Larry Hill]

I am building a dining table and wanting to use mortise and tenon for the legs and aprons. What size tenons should they be? I'm thinking about 1/4 inch thick, but think that might not be enough. The aprons will be about 7/8 inch thick, maybe 13/16, don't know for sure what demons ion would be the best. Also, about how long should they be, 1/2, 3/4, or full inch long or longer? Thanks for any ideas or dimensions you have used!

[lowell holmes]

I wouldn't make the tenon less than 3/8" and preferably 1/2". If I went with 1/2", the apron would be 1" thick. Dining tables are moved from time to time. The apron to leg connection absorbs a lot of stress when it's moved.

[Larry Hill]

I wouldn't make the tenon less than 3/8" and preferably 1/2". If I went with 1/2", the apron would be 1" thick. Dining tables are moved from time to time. The apron to leg connection absorbs a lot of stress when it's moved.
How long should or would you make the tenons?

[Brent Ring]

I always make my tenons for tables at least 1/2 to 2/3rds of the width of the leg they are going into. If possible I miter them so that the tenons from the aprons meet and can glue together in the mortises. I agree, 3/8 or 1/2 think for a dining table. I have made end tables and other smaller pieces where 1/4 provides sufficient strength. My Workbench has 1/2" wedged thru tenons.

[John TenEyck]

Typically tenons are 1/3 the thickness of the stock and the length is at least 3 times the thickness. So for a 1 inch stretcher the tenon would be about 3/8 thick and 1-1/8 long.

[Jim Matthews]

Remember two things, dealing with legs and mortises -

The adjoining stretchers will 'meet' at right angles.
The amount of material on the side of a mortise determines the strength.

If you can divide the width of the leg into thirds; one third for the mortice,
and a third on each side, it should be strong enough to last.

In practice, I like to hide a little extra 'meat' on the inside portion of the leg,
at the top where stretchers cover it. That way, I can cheat a little toward
the midline of the leg to avoid weakening the leg.

I like to have my stretchers 'inset' from the leg surface for a slight reveal.
Flush stretchers look wrong to me, although I couldn't say why.

If the tenon from the stretcher is more than twice as "high" as the leg is wide,
I split the tenon in two, like an old skeleton key.

[Chris Friesen]

Thicker tenons are stronger. a 1/2" tenon in 7/8" stock would give you 3/16" shoulders if you centered it. Note that the inside of the aprons doesn't technically need to be finished or smooth or flat.

Technically the strongest M&T joint is where you have equal amounts of wood in the tenon and both mortise walls combined...so the mortise can be up to half the width of the leg.

You want the tenon as long as possible, up to about 5X the thickness of the tenon (beyond that you gain little). If you place the mortise closer to the outside so it's not centered on the leg, you can make the tenon a bit longer.

You want the tenon as wide as possible, up to about 4". Beyond that and wood movement can be an issue.

Miter or notch the tenons so that they fit together. I've seen a truly meticulous joint where the tenons were dovetailed where they met inside the mortise. That might be overkill.

[Dennis Peacock]

I moved the thread here for better exposure and response.

[Rod Sheridan]

Hi Larry, I would make them about 1/2" thick and 1 1/2" long.

I would have the apron go into the leg closer to the outside so that I have maybe a 1/4" reveal, this will help with more wood on the inside where the two tenons intersect.........Rod.

[Jim Dwight]

The only thing I would add is I do not typically have the two mortises meet. I don't think the resulting mitered tenons are much stronger than stopping each tenon where they meet (you get more long grain connection on the outside of the joint but not on the inside. End grain to end grain doesn't add much). I normally mortise a little deeper than the tenon is long and if you do that with a mitered joint you actually loose the extra long grain connection anyway. It gets cut by the opposing mortise. An alternative would be to stop slightly short and pare to size with a chisel. Or be real good with the depth for each mortise and the length of each tenon.

So I would make the tenon as long as it can be with the mortises not meeting. I would also make it at least 3/8 and probably 1/2 inch thick. I would make the outside shoulder smaller to get more length on the tenons.

[Rick Lizek]

http://www.rockler.com/surface-mount-corner-brackets-for-table-aprons
Sure you don't want the legs removable?