lewisc

How would you join this?

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I'm looking at this couch and wondering how it would be joined. I imagine some sort of mortice and tenon as I can't see a plugged hole hiding a bolt.

How would you join the legs to the inside frame to maintain the stresses this couch would go through? Maybe a pocket hole screw?

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Threaded rod in the leg, captured nut in the bottom of the seat frame. Even with hardwood, as pictured the seat will sag a bit in the center unless they have some sort of steel that cannot be seen. 

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Looks like the legs have a frame laminated to their inner edges. Could be used to conceal a bolt such as Carus suggested, with the main part of the leg glued on after assembly.

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I'd do what Carus showed, only instead of those wooden dowels I'd use steel rod and West Systems with 404.  For the leg assemblies, Dominoes or dowels would work.  I think it's a pretty poor design structurally in general, because there's nothing to resist racking in the legs.  I would probably not build it at all because of that, or revise the design.

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This piece of furniture was probably designed by a newbie woodworker :
no wood selection, knots everywhere, no grain aesthetic concerns, poor joinery.

But I believe racking issues are limited here : there's a large contact surface between the back and the arms.
I would use 1/2"(12mm) dowels along the joints, lot of them...

I agree with Eric. I would probably revise the design too : first, hiding the end grain with miter joints (hidden dovetails or dowels),
then probably extend the back to the ground or adding a rail running under the seat, centered with arms/feet.
The front rail of the sitting area would benefit of a Maloof alike wood joint for extra strength.img_sammaloof_8.jpg?timestamp=1494355531

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Guest Randy

If own a Domino, I would probably use dominos on all joints. It's fast, easy and strong. If not, then dowels could work. possibly half lap joints on the arms. It's even possible to put the arm assemblies together with large screws and glue and plug the holes with plugs cut from the same wood you do the arms with. If you're careful you can make them flush and almost invisible (or do them with a different wood as suggested and make it part of the design). 

As for the arms to the frame, if not Dominos, then the suggestions in the other posts would work.

I would agree that the overall length of the couch will likely result in sagging at some point without some support underneath. Couches must hold a lot of weight and there doesn't appear to be anything in the center to hold that weight. If there isn't a need for such a long piece of furniture, draw one shorter and see how that looks. Shorter would be better structurally.

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I'm more interested in how this would be made rather than building it. It's from a furniture maker a few hours from me and I was browsing their site and found it. I'd be curious to see what happens if some sat in the centre with a bit of force.

It does fit in with what I would call "in" at the moment over here. There's a bunch of these tables that have huge timber tops but not much in the way of support for legs. Basically a square of metal welded together and bolted to the table top. I had a look at one the other day and the top looks and feels nice but I don;t know how it will stand the test of time.

 As far as the look of the timber, I'm pretty sure they use reclaimed timber so there's some nail holes etc. The type of timber (messmate) is one of our common ones. It generally has gum veins, knots etc and IMO looks nice when epoxied. 

 

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Guest Randy

I wouldn't think the lack of support in the middle would be a huge problem for the table. Generally tables don't require the type of weight capacity that chairs do. 

A couch as long as the one in the picture has too large a span between the ends. If you put 2 people near the middle of the couch, I'd be surprised if it didn't sag almost immediately unless there are some steel rods or bars attached to the frame's underside supporting the seating area across the entire span. That may be a possible answer to  the seat support issue; a steel bar or rod imbedded in the two arm structures spanning the entire length of the couch on the underside of the frame; one in front and one in back. If you kept them far enough from the outer edge, it wouldn't be visible.

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13 hours ago, lewisc said:

It does fit in with what I would call "in" at the moment over here. There's a bunch of these tables that have huge timber tops but not much in the way of support for legs.

Begin rant.

That's because people don't know how to build things, and consumers don't know how things are supposed to be built.  Just half-ass it and rely upon the ignorance of the public for sales.  It works, why change it?  If there is no support under that table to resist racking forces, it's absolutely under-engineered.  That doesn't mean it's gonna topple over when people are eating at it, but if you bump a corner with your hip, I bet it wobbles.  And it's not the right way to build a table...so it shouldn't be done that way simply on principle.  Not to mention, it looks stupid.

Every time someone buys a slab at the yard, I always ask them what they plan to do for the base, and half the time I get this blank stare as if they hadn't even given it any thought.  The other half usually say they're gonna screw some metal crap to the slab...which makes for a table that looks like you just screwed some metal crap to a slab.  People don't seem to understand that the base is half of the build...the part that requires almost all the skill...and honestly it's the part that makes or breaks the table.  It takes artistic vision and an understanding of aesthetics and construction to pull off a slab table, and people don't have it...so they shouldn't try.  Leave it to Nakashima, who did it right.

My mom had lunch with me at the yard one day, and after we ate she was looking at the slabs.  There was a small one there that she said she really wanted for her family room.  I asked her what she was gonna do with it and she said, "I have this neat antique wheelbarrow in the backyard and I can just set the slab on top of it."  I kicked her out of the lumberyard and haven't spoken to her since.

End rant.

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Speculation: Reading the discussion, and thinking about the side image, I'm pondering there might be 8 or so truss rods or torsion bars, like I beams, through the seat. Sort of like a guitar neck, only much larger. That wood under the seat looks about 2" thick. It could easily hide them. It would take that many to counteract the torque ("racking") of a person sitting in the middle. And even then a large person would easily be too much for it. It might be a mixed-medium "engineering marvel" with the features hidden inside the wood. Or, as @Eric. says, it might be shoddy design: Stylish but functionally inadequate.

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Gonna have to agree with the nay sayers. Sure it has that modern/rustic look people seem to like right now but its an all around poor design from stem to stern. It wouldnt take long for that to be a wiggly sagging mess unless theres ALOT of hidden steel. And even then...

 

 

 

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