Tenon sizing - first time

[Carson Saunders]

I feel like I’ve read dozens and dozens of articles and posts about tenon sizing, but I’m still a little unsure and would love some advice as this is my first time with M&T.

I’m joining 1.5” square red oak to other 1.5” square red oak. My original thought was a 1” long tenon that is .5” square, but that just seems a little weak to me. Would it be better to make the tenon with a .5” edge cheek but a 1” face cheek? And is 1” length ok or too long?

Any input is appreciated. Thanks.

[Mark Hennebury]

There is a lot of flexibility in making those choices, depending on many things, like what the joint will be used in, what are the types of stresses that will be applied etc.
You can do a full depth tenon (all the way through) or a stopped one of 1" like you said.
You can do one third the width like you said, so .5" which is a good starting rule of thumb.
The length or the mortise can be the full 1.5" but probably better to have shoulders all round as in the sketch which the tenon length is 1.3". The shoulders only need be small on the length side, 1/10" is fine.

the thing is joinery is a search for the perfect proportion, you are looking to find that perfect balance of removing and leaving the right amount of material in each piece to perform the task that is required of it. There are many variables depending on the specific job and material, so it is not easy to give specific measurements. You have to experiment and learn as you go.


mortise and tenon.jpg

[Carson Saunders]

There is a lot of flexibility in making those choices, depending on many things, like what the joint will be used in, what are the types of stresses that will be applied etc.
You can do a full depth tenon (all the way through) or a stopped one of 1" like you said.
You can do one third the width like you said, so .5" which is a good starting rule of thumb.
The length or the mortise can be the full 1.5" but probably better to have shoulders all round as in the sketch which the tenon length is 1.3". The shoulders only need be small on the length side, 1/10" is fine.

the thing is joinery is a search for the perfect proportion, you are looking to find that perfect balance of removing and leaving the right amount of material in each piece to perform the task that is required of it. There are many variables depending on the specific job and material, so it is not easy to give specific measurements. You have to experiment and learn as you go.


mortise and tenon.jpg

Thanks for the feedback Mark.

I'm building a nightstand/bedside table, so I would think the stresses would be minimal. These mortises will be used to connect the side and front/back supports (I suppose they could be referred to as aprons although they are only a portion of it) to the legs. I do prefer the look of a stopped tenon for this particular design. I also have the added complexity of interfering tenons, so I plan to miter them to solve that. I may go with the .5" x 1" tenon size since that just seems beefier to me. I do have some scrap stock that I can do a few trial runs with, so maybe I'll experiment a bit to see what works.

[Mike Cutler]

I feel like I’ve read dozens and dozens of articles and posts about tenon sizing, but I’m still a little unsure and would love some advice as this is my first time with M&T.

I’m joining 1.5” square red oak to other 1.5” square red oak. My original thought was a 1” long tenon that is .5” square, but that just seems a little weak to me. Would it be better to make the tenon with a .5” edge cheek but a 1” face cheek? And is 1” length ok or too long?

Any input is appreciated. Thanks.

The "rule of thumb" would size your tenon at 1/2" thick 1" deep and 1" wide.
I personally would make it 3/4" thick, 1" deep and 1" wide.
It would really help to know what the mortise was supporting and in what plane.
If this is a top rail, going into a leg, I would make sure that the mortise did not extend any closer than 1/2" from the end of the leg.
Rules of thumb are meant to be broken sometimes though.

[Scott Winners]

For 1.5 inch square oak versus bed side table/ night stand loads I agree you have a lot of flexibility. No wind load, no snow load, probably no one dancing on it. I would stick with 1/2 for the tenon thickness/ mortise width, think about someone using it as a stool to sit on someday when you aren't looking is all the strength I would be worried about. Make it pretty, it will be strong enough.

[Scott Winners]

I did think of one other thing. If you can come up with tenons at 1/2 x 1x 1 inches like Mike and Mark talked about, and have it look good to you, well, that thing will very likely be strong enough to stand on. Pin oak, swamp oak, live oak, doesn't matter. If you got those tenons with minimal grain runout and no big knots, reasonably tight, you could stand on it to change light bulbs or smoke detector batteries when no one is looking. Save dragging a step ladder through the house from garage to bedroom too. Use a good dust rag so you don't leave footprints on the table top.