# I hope that's a strong joint



## johnhutchinson (Dec 9, 2013)

I just saw this mid-century-modern chair in the Modernica blog …

http://blog.modernica.net/weekend-los-angeles-modern-auction/?utm_source=rss&utm_medium=rss&utm_campaign=weekend-los-angeles-modern-auction

To me, the bottom leg joint looks like a lawsuit waiting to happen. I'm now wondering if it ever went into production. I have a Heywood Wakefield lounge chair with a similar joint where the arms meet the legs, but *NOT* where the legs meet the sleds.

I'm calling it a Dirty Harry (Feelin' lucky, punk?) joint. Your thoughts?


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## a1Jim (Aug 9, 2008)

A very cool design .I really can't see what kind of joint was used ,but it does take lot's of stress for sure.


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## Mahdeew (Jul 24, 2013)

Holy crap! Just looking at it makes you want to find an alternative seating area.


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## johnhutchinson (Dec 9, 2013)

*Jim:* I'm betting that dowels were used in the joint … VERY STRONG DOWELS. That seems to be the joinery-of-choice for the period.

*mrjinx007:* Are you saying that you wouldn't want to flop into that good 'ol recliner?


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## stefang (Apr 9, 2009)

This looks like a pretty strong construction to me John. The bottom rail on the arm reinforces the joint on the top of the arm and I'm pretty sure the seat must be constructed to provide the backwards or rocking motion. Another clue to it's solid construction is it's age, which looks to be at least 30 or 40 years old or possibly more.

I had some leather chairs with a very similar look to it, but made with continuous bent laminated beech with no joints in the arms. I bought them in the 80's and my son is still using them in his basement. They are 'springy' and comfortable.


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## johnhutchinson (Dec 9, 2013)

*Mike:* Good point on the age, but I wonder if the 'sitters' lived that long. 

Mies Van Der Rohe did a similar chair, but he decided that steel was a better way to go.


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## Mahdeew (Jul 24, 2013)

I have 240 pound (mostly muscles) friend sit in one of those 60's made metal pipe chairs and he stared to rock on it and next thing you know, he was doing backward flips in my garden behind him. Likely, he didn't suffer any injuries. I think this design is more likely to fail at the bottom rather the top rails. Looking at the wight distribution, the pressure would want to tear that bottom joint apart. Yea, dowels would definitely prevent that tear out-not.


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## screwikea (Feb 1, 2013)

Hey stefangm I think you missed what he's talking about-there's basically a butt joint coming into the part of the legs on the floor. So there are some fasteners or something happening in there, but it's a WHOLE lot of shear force getting thrown into the butt joints. Like with what mrjinx007 pointed out, if you get someone leaning back into the chair hard enough they'll pop the joint.



> This looks like a pretty strong construction to me John. The bottom rail on the arm reinforces the joint on the top of the arm and I m pretty sure the seat must be constructed to provide the backwards or rocking motion. Another clue to it s solid construction is it s age, which looks to be at least 30 or 40 years old or possibly more.


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## bondogaposis (Dec 18, 2011)

Americans weren't as big back then.


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## jmartel (Jul 6, 2012)

It would be strongest to use a bridle or a half-lap joint on those. Dowels do little to add strength.


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## TheFridge (May 1, 2014)

Veneered possibly?

I don't see a seam along the front at the top or bottom.


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## JAAune (Jan 22, 2012)

At first glance it looks like a weak dowel joint but a more careful examination indicates that there's a rim of bent wood going all the way around the leg. That curved piece looks about a quarter inch thick or so and may either be steam bent or laminated but probably the latter.










What that outer lamination accomplishes is eliminating the pulling force on the joint between the foot and the leg. Instead of wanting to pull apart, it's forcing that joint into compression and all the pulling force is directed at the seamless piece of bent wood. A dowel joint can withstand compressive force with ease.


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## AlaskaGuy (Jan 29, 2012)

Could be something like in this video.


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## johnhutchinson (Dec 9, 2013)

*AlaskaGuy:* Thanks for the Thomas Moser link. He's been a hero of mine since Day One !!!
I think he defines modern American furniture.


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## intelligen (Dec 28, 2009)

WOOD Magazine's ZigZag chair elicited similar concerns, so they tested their joint.


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## Mahdeew (Jul 24, 2013)

Rob, that was amazing. Hard to believe that piece held up under that much pressure. JAAune, 1/2" bent oak wood would have somewhere around 5000 lb of shearing resistance. Not sure how many pounds that would translate into with let say a 200lb person fully seated on that chair.


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## johnhutchinson (Dec 9, 2013)

*Jacob (aka JAAune):* I'm nominating you for the *Columbo Prize For Woodworking Investigation. * 
I think you nailed it with the bent laminations. There *IS* more to the joint than first meets the eye.

PS - Keep your laser warm. Incoming soon.


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## Yonak (Mar 27, 2014)

I would think a lag bolt, screwed up from the bottom, would help immensely.


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## Loren (May 30, 2008)

Great eye, JAAune. It makes sense. Otherwise it would
have this end-grain thing going on. I'll bet the designer 
was after a way to solve the end grain issue and the 
strength is an added byproduct. I have seen this sort 
of chair joint done with exposed end grain too. I figured 
it was done with mortise and tenon.

I look at a lot of chairs.


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## JAAune (Jan 22, 2012)

Could be a mortise and tenon in there but for some reason I'm thinking it's a commercially produced chair so that's why I'm guessing dowels. We'll never know unless someone wants to go buy it and take it apart for everybody's benefit.

@JohnHutchinson,

Laser is ready to go as always.


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## JAAune (Jan 22, 2012)

Here's a fun tip. You can click and drag a picture into the search box and sometimes you'll find search engine entries for the picture. I just did it now for the chair and got some more info.

Link to a larger resolution picture.
Large Resolution Photo of Airline Chair

Auction info
Sotheby's Auction Entry

And some info on Kem Weber. He's an industrial designer which seems to confirm my theory that it was produced commercially.

Kem Weber

And the airline chair was RTA in the days before IKEA.

Article on Chair

I'll take that Columbo prize now just so long as it isn't a car.


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## johnhutchinson (Dec 9, 2013)

*Excellent research, Jacob !!!* 
My favorite quote from the articles …
"Weber's aesthetic may have struck some of his younger contemporaries as quaint, but in other ways he was perhaps a bit too ahead of his time." 
Gotta love his picture. In a lot of ways he LOOKS like a private detective.


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## bigblockyeti (Sep 9, 2013)

I can't help but wonder if it's not set up a bit like a box joint, only with long, thin intersecting fingers giving tremendous glue surface area. Dowels would work great for alignment, but the strip of wood around the outside could see tremendous stress, up to 3ksi by my math with a heavy sitter.


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## CFrye (May 13, 2013)

Very interesting discussion, John. Always learning on Lumberjocks.


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## Mahdeew (Jul 24, 2013)

Another questionable design?


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## shawnn (Aug 30, 2014)

My Chinese name translates to "He Who Breaks Chairs"....I would sit elsewhere!


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## distrbd (Sep 14, 2011)

> Another questionable design?
> 
> 
> 
> ...


Good looking chair but I would hesitate to sit on it.


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## Mahdeew (Jul 24, 2013)

There must be something in the back that offsets the weight to the top rail?


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## JAAune (Jan 22, 2012)

That's a Nakashima design. It looked familiar because I'd seen it in one of the biographies I've read but couldn't remember which one. Had to Google it to find out.

If anyone wants an original, it looks like they're for sale at the site linked below. I'm sure they function just fine otherwise Nakashima wouldn't have gotten the reputation he had.

Conoid Chair


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## Mahdeew (Jul 24, 2013)

JAAune. pretty wild. Almost looks like those self-balancing wine bottle holders.


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