# Joint Design



## Zach117 (Jan 8, 2010)

I need suggestions on a joint design for the piece below. Dimensions will be 34 inches long by 11 inches wide by 1 3/4 inches thick. I don't see how I can make the design out of a single piece of wood. Mainly, I cant figure out how to cut the interior radius on the bottom for an 34" x 11" wide board.

My thinking is to make it three pieces seen in the second picture. A flat 3/4" board attached to each 1.75" end piece. The easiest way I can think of is to attach end grain to end grain and use a floating tenon such as beadlock. Cut the 11" width into three pieces as well to be wide enough to fit three floating tenons and glue the middle one only similar to a breadboard end style. My only other thought was a half lap joint, but I would like to avoid the "Z" shape of the joint on the front. Looking for it to be more seamless looking.

Any thoughts on an easier or better joint?


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## therealSteveN (Oct 29, 2016)

It looks to be something that would favor either a dowel at the lower end, or a Domino at the upper, with the Domino being the quicker, and easier of the 2. There are actually several available systems to make a dowel like join. I don't have any of them, but have seen Beadlock, I've seen others, but can't recall names for them.

Your issue as you have already stated is end grain, so something to cross is needed for strength, and glue surface where it won't just get sucked up in the end grain. All of the above are the invisible joints. It's possible to box, or Dovetail I suppose, but that sort of squashes seamless, unless you would want to turn it into a feature.

Router joints like a lock miter are generally going to be more for pieces at right angles, yours is really a straight line join, but a lot of folks set up their Lock Miters flat to check for fit, in that attitude they do offer a lot more glue surface, but they are going to be fussier than dowels, or Dominos. Plus with the lock miter it would either be seen from the edges, or require more work to hide it.










Sitting looking at your pics. I don't think I'd sweat the join, it's the glue up I wouldn't want to mess with. Thinking you might need to make a jig. Something to take the curve you are introducing, out of play. Chairmakers probably figure that out in short order though. They are all the time clamping parts that have no business being together, and making it look easy.


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## SMP (Aug 29, 2018)

Personally i would change it so the top goes all the way across and has rounded ends, and the little "feet" are glued to the bottom side of the top piece and then curved as needed to match up to the top.


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## Unknowncraftsman (Jun 23, 2013)

I think your asking for trouble with the three piece design. All those joints with wide short grain pieces too much room for error.
Even the whole one piece design has its challenges. That's the road I'd take.

Good Luck


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## RichT (Oct 14, 2016)

> It looks to be something that would favor either a dowel at the lower end, or a Domino at the upper, with the Domino being the quicker, and easier of the 2.
> 
> - therealSteveN


Domino? Perhaps the OP doesn't own one (I didn't see a reference to it in the post), and does not care to spend the $1000 to buy one.

This one's a no-brainer. Instead of trying to join the pieces as you have shown, mill and glue the piece to the underside of the shelf. That way you've got long-grain and it will hold just fine. Also, the joint will be less visible on the edge grain that it would on the surface.


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## therealSteveN (Oct 29, 2016)

> It looks to be something that would favor either a *dowel at the lower end*, or a Domino at the upper, with the Domino being the quicker, and easier of the 2.
> - therealSteveN


Dowel

Also usually very low cost.

Kindly get off my back.


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## RichT (Oct 14, 2016)

> It looks to be something that would favor either a *dowel at the lower end*, or a Domino at the upper, with the Domino being the quicker, and easier of the 2.
> - therealSteveN
> 
> Dowel
> ...


I think we all know what a dowel is. The Festool Domino is an awesome tool, but costs $1000.

If a drawing is needed, I'll provide one, but it's no different than gluing edging strips under a shelf to make a 3/4" edge appear to be 1 1/2", except that this one has profiles milled before attaching.


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## RichT (Oct 14, 2016)

Back to the OP, you could do a cove cut on a strip of wood (cross grain, so it matches the end grain of the shelf), glue it to the underside of the shelf, and then do a round over cut along the top edge to complete the profile. Let me know if you'd like more detail, and I'll be happy to provide you with a sketch.

The major advantage of adding moulding to the underside of the shelf is that it's parallel grain, so no *dowels* or *$1000 dominos* are needed.


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## MadMark (Jun 3, 2014)

Spline it.


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## RichT (Oct 14, 2016)

No one seems to be able to get away from the end-grain joint. Don't do it that way.










A cove cut on a strip, glued to the underside of the shelf, and the shelf edge then rounded over will give you the profile you want.


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## Bstrom (Aug 30, 2020)

> No one seems to be able to get away from the end-grain joint. Don t do it that way.
> 
> 
> 
> ...


SMP and Rich seem to have this figured out well - for strength and appearance.


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## ibewjon (Oct 2, 2010)

+1 for Rich and SMP. Don't make it harder than it needs to be.


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## LeeRoyMan (Feb 23, 2019)

No Joints….....Use 8/4, 
rout your 2 coves first, 
then use a dado blade and remove the rest of the middle area.


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## AndyJ1s (Jan 26, 2019)

I agree that if you want to do each end in two parts, the long-grain to long-grain joint will be far stronger, and the seam on the outside will be down on the curve and therefore less visible.

But there are ways to do this in one piece, by cutting the coves on the router table, or a table saw.

Fine Woodworking had a very good, detailed article on the setup and technique. It even went into setups for tilting the saw blade for asymmetrical coves.

The rest could be done on a slab flattening jig, or hogged out with a dado blade or a dado/mortise bit in a router table.

But all this begs the question: what is this piece for, and how will it be joined to apparent other pieces in the project? That may impact the choice of an optimal solution.


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## Zach117 (Jan 8, 2010)

Thanks for the advice everyone! It seems that this method might be easiest. Didn't think of it. For the bottom piece, cut the interior curve using a cove bit on the router table and then use a round over bit "freehand" for the outside curve at the top?

This is indeed a shelf. It will be the top shelf for a bookcase. There will be four tenons, end grain, going into the four corners of the bottom of this shelf where mortises will be cut.

[/QUOTE]


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## DS (Oct 10, 2011)

+1 to LeeRoyMan's suggestion to use 8/4

I might make this in longways rips, cut the rough profile on the bandsaw, route to final size with a template and flush trim bit in my router table, then glue them together to get my overall width.

(What I would actually do is write a program for the CNC to cut it with the 3" long, 5/8" diameter low helix bit, out of the 8/4 board, making half a dozen identical pieces in as many minutes, then just glue them up and sand it. But, you might not have access to that tech, so…)



> No Joints….....Use 8/4,
> rout your 2 coves first,
> then use a dado blade and remove the rest of the middle area.
> 
> - LeeRoyMan


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## Zach117 (Jan 8, 2010)

As far as the mortises going into the bottom of the shelf with the above design, would you cut those last by hand using A drill bit and squared off with a chisel? I have a small grizzly hollow chisel mortiser but I think this piece, 34" x 11", will be too big for it.


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## Loren (May 30, 2008)

I might approach it by routing a rabbet in the top board and moving the long grain up maybe 1/2" from the suggestion in the image. You'd have a little vertical line and room to carve the transition in the shape if needed. Still you'll have a glue joint visible on the end grain in the end.

If that end grain joint visibility isn't acceptable, my choice would be the original plan using dowels.

This is one of those sort of things architects and designers like to draw but not pay for. Of course CNC makes things easier these days.


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## MPython (Nov 30, 2018)

Derek Cohen has an extensive photo on how he did it on his blog here: http://www.inthewoodshop.com/Furniture/AnotherCoffeeTable5.html


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## Zach117 (Jan 8, 2010)

Here's a prototype using the joint suggestion.



















It ended up being not as thick as I mentioned, only 1 3/8" instead 1 3/4" due to the cove bit I had only being 1/2" high. So many router bits Ive purchased for this project already…I'm think I'm going to use a bigger round over bit, also need to buy, 1" radius. What do you think, does it need a bigger round over on that exterior corner?
Thanks for all the suggestions so far!


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## Zach117 (Jan 8, 2010)

These photos will not flip for some reason…


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## Phil32 (Aug 31, 2018)

You can make the cove cut on a table saw by making a fence jig at a slight angle to the blade. Only cut about 1/8" per pass over the blade.


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## RichT (Oct 14, 2016)

Looks great. Regarding the round over radius, I think it looks fine, but what really matters is what looks good to you.


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