# Table leg tenon



## KelleyCrafts (May 17, 2016)

All, I'm making some table legs that are wide, you'll see something similar in the pic. I was curious how deep the mortise and tenon should be to join the base piece with the top contrasting wood?

Any input is appreciated.


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## wuddoc (Mar 21, 2008)

Are you:
1. Discussing a conference room table?
2. Considering an underside top supporting structure of rails with mortises?
3. Considering legs mortised directly into the table top?


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## KelleyCrafts (May 17, 2016)

Good questions I should have answered. The table will only be 7' long, nothing this long. What I was refering to on the mortise and tenon size would be the depth of the bottom part that's clearly a different wood attached to the longer leg parts up to the table.

As for the whole leg section, it would be attached to railed structure with cross beams mortise and tenon to each other as well. Then the top would be secured to allow movement.

So mainly the pieces that form the leg….I'm curious if 1/2" would be enough or if I should have more. I'll have a trestle like this one plus the top support structure so it should be very sturdy but I don't want this to be the breaking point.


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## a1Jim (Aug 9, 2008)

I assume you're talking about the base pieces M&Ts not connecting the top to the base with M&Ts(not a good idea ? Depending on the width of the horizontal and vertical pieces, if that's the case I would suggest tenons somewhere in the area of 1/3 the width of the material.


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## KelleyCrafts (May 17, 2016)

Thanks Jim. I am talking about the base piece that holds the trestle and attaching it via tongue and grove/M&T to the other two leg pieces on either side of it. The material will be 6/4, haven't decided definitively on the width yet, I've been drawing designs to see what I like.


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## wuddoc (Mar 21, 2008)

Jim is spot on referencing the sizing of 1/3 as each shoulder is 1/3 the width of the rail leaving 1/3 for the tenon.

A blind or stub tenon length from the shoulder might be at least 1/2 the wood thickness but not to exceed or allow the tenon to go entirely through. A chamfer is helpful all around the tenon end to ease entry into the mortise.

The lower connector (rail) of the legs might be a stub or blind mortise-and-tenon joint however by enlarging the picture you included, each rail and or leg(s) has a radius. If that is the case I am not sure what type of joint would be used to connect the rail and leg(s).

Please note a 1/16" to 1/8" gap between the length of the tenon and the depth of the mortise allows for excess glue. With no place for the excess glue when you are pushing the tenon into the mortise, hydrostatic pressure occurs and can force the glue out of the wood at some point where the cell leg grain structure is weakest.

If you are asking about the bottom unit (stretcher) connecting the pairs of legs from the front of the table to the back it may be a open mortise-and-tenon joint, dado, dovetail, or combination of these joints used for design emphasis.


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## KelleyCrafts (May 17, 2016)

> The lower connector (rail) of the legs might be a stub or blind mortise-and-tenon joint however by enlarging the picture you included, each rail and or leg(s) has a radius. If that is the case I am not sure what type of joint would be used to connect the rail and leg(s).
> 
> - wuddoc


This is what I'm talking about. I think it's tongue and groove and was thinking about doing just that by am unsure it's going to be strong enough.


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## a1Jim (Aug 9, 2008)

I still see no problem with the use of M&T joinery for the bottom rail it will still be plenty strong as far as a radius is concerned the M&T can be made before the member's radius is milled. In my opinion, the bottom stretcher has far less stress than the top stretcher below the table top. Both should be plenty strong with the use of M&Ts or a saddle joint perhaps with the addition of pegs or even a sliding dovetail.


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## KelleyCrafts (May 17, 2016)

A sliding dovetail would look great but the dovetail would be cut from the end grain of the vertical pieces so I'm not sure that would be strong enough if you're saying to slide it onto the bottom horizontal piece that takes the tresses edge. I could be wrong though, I'm up for education on this. It's not a standard thing so help is appreciated. It'll be my dining room table.


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## Iguana (Jun 22, 2011)

To me, it looks like those leg assemblies are 5 pieces. The bottom rail, obviously, and then 2 pieces on each side. The outer piece is straight and would use a M/T joint to the bottom rail. And the inner piece has the inside radius, glued to the outside piece only. Where it contacts the bottom piece would be located with a spline (or T/G) to allow some movement without losing alignment.

I built some 3-piece legs like this (minus the inner radius) used a double loose tenon for joinery. Each mortise was 3/8" thick and 3 1/2" wide. Just under 3/8" between them. The mortises were as deep as I could get with my router, about 2" - so the loose tenons were not at under 4" long.

All jn all, it was pretty easy using a simple mortise jig for the router. Adding the inner radius piece would be straightforward.


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## a1Jim (Aug 9, 2008)

What I'm talking about is the trapezoidal shape seen on the bottom end of the table. As long as you're using a hardwood it will be plenty strong unless you planning on parking a truck on top of the table.


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## KelleyCrafts (May 17, 2016)

Mark…I think the radius on the horizontal bottom piece is part of the horizontal bottom piece. Now looking at the picture closely on my phone which is just slightly better than what shows up here, the vertical pieces might be two pieces which would indeed make it easier to do. The bottom piece holds the radius and I think the grain stay consistent throughout.

Jim that makes sense too. Would be sad to cut a sliding dovetail that's hidden. Lol it would be strong though for sure since it's the side grain on both pieces.

I think this has gotten more confusing. Lol


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## KelleyCrafts (May 17, 2016)

Mark, that's two vertical pieces on each side of the leg so four vertical and one bottom horizontal.


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## Iguana (Jun 22, 2011)

Yeah, that's what I was trying to explain, apparently not very well  The inner vertical pieces have the radius. And are added after the outer vertical pieces have been joined to the horizontal piece. Purely aesthetic and non-structural.


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## KelleyCrafts (May 17, 2016)

Gotcha. Makes sense. I think I've decided on a loose tenon to join it. 2" deep likely maybe more of I use the drill press and forstner. If I want to use the router I'll need a new bit.


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## Mikesawdust (Jan 29, 2010)

My vote would be a through tenon, I think the contrast coming through would look good and maximum glue face


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## HokieKen (Apr 14, 2015)

> My vote would be a through tenon, I think the contrast coming through would look good and maximum glue face
> 
> - Mikesawdust


That's what I was just thinking too. Maybe even leave the tenon a little proud with chamfered ends and pin/drawbore them with contrasting dowels. Seems like a lot of work for the base of a trestle but, I'm not sure it's really any more work than blind M&T.


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## KelleyCrafts (May 17, 2016)

Thanks for the input guys. I'm probably a couple of weeks away from doing the legs but I need to plan it out incase I need anything special I need to order.

I do like the through tenon idea out of the side of the legs, then maybe tongue and grove the top part 1/2" for alignment or movement at the top part of the bottom horizontal. I don't know about the proud ends but I'll do it and check it out, if I don't like it I can cut them off. I could get fancy and use brass dowels through the tenons. I imagine there would be at least two tenons 2" wide going along the edge, maybe three but likely not.

The wood for this will be red eucalyptus for the bottom horizontal and then cottonwood for the vertical legs. so they will be contrasting already, I'll take more ideas if any have them. I wouldn't have thought to do the through tenons but think I like that best so far If I can make them come out clean enough. lol


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## HokieKen (Apr 14, 2015)

Brass would look nice but a Eucalyptus pin would tie the contrasting woods together IMHO.

Thinking along the same lines, if you decided on a through tenon with the tenon flushed-up to the leg, you could do a wedged tenon with a cottonwood wedge. Just thinking that would allow you a little more slop in chopping the mortise.

I was happy with how these through-tenons worked out but in hindsight, I wish I would have pinned them with Walnut dowels or flush cut them and wedged them with Walnut to tie the pulls in with some other features. Just my $.02…


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## KelleyCrafts (May 17, 2016)

Nice dresser buddy! I would agree with your after thoughts but wouldn't complain about how that turned out none the less!

OK, See how easily I'm swayed on this one…lol This table is something I want to last far beyond me. Hopefully one of my non-existent grand kids will use it someday. So I'm struggling to see what's best. I think the cumulative might have me swayed so far.

I'll do the through tenon, likely I'll cut them flush and probably do a cottonwood wedge and I'll turn some red eucalyptus dowels for the thing. Thick ones like 1/2" or 3/4" so they show up well. Unless someone else chimes in. lol


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