Zigzag rocker in jarrah

[Rocker]

I built this zigzag rocker based on a design idea proposed by a fellow member of the Australian Woodworking Forum.

The miter joints between the legs and the rockers each have twin miter keys that provide a total glue area of about 100 square centimeters in each joint, apart from the 35 square centimeters of glue area on the miter joint face. The back rails and the seat cross-rails are Dominoed.

The seat side-rails and the rockers are splayed at an angle of 7 degrees to the chair's vertical plane of symmetry.

The leg/arm miters are glued and screwed into 10 mm-deep housings cut in the back stiles, and the seat side-rails and the legs are joined by interlocking 5 mm-deep housing joints. There are no stretchers.

Rocker

 

[Fred West]

Rocker, what a beautiful chair. I went to your website to try and find the plans but everytime I clicked on the link to lead me to the plans I received error messages. Don't know that I can do it justice but would love to try. Thank you, Fred

 

[Rocker]

Fred,

Actually, the plans to which there is a link on my blog are for a different rocker (the one shown in my avatar), which has a similar look to a Maloof rocker. However, if you give me your e-mail address in a PM, I will send you an article on this rocker which I am hoping to get published shortly.

I don't know why the link from my blog won't work for you; are you using IE as your browser? It works on that.

Rocker

 

[ROb McGilp]

Hi David,

That chair looks great.
I confess I initially thought the design a little austere, but it really does look good now.

Regards,

Rob

 

[Eli]

If your original rocker and your zed chair had babies, this would be the beautiful child. Nice work.

 

[Dave Rudy]

WoW!  What a beautiful chair.

 

[Fred West]

David, I responded via email and thank you. Fred

 

[iggy07]

From your description the miter joints would be quite strong, but visually, I can't help the feeling of "That looks great, but I wouldn't want to break it!" Other than destructive testing, how do you know what the weight limit would be? Or do you know from experience that this would not be a problem.

(On his first visit to meet my mom's parents, my dad sat in an antique chair and broke it! Great way to make a first impression, huh? Since he weighed all of about 160 lbs at the time it probably was not really his fault. I guess it worked out OK; they were married 42 years, and my grandparents eventually moved from Boston to Seattle to live near us.)

This chair reminds me a little of the new glass-floor observatory on the rim of the Grand Canyon. When you walk out on it you are looking (straight) down about 2,500 feet. I'm sure it's safe, but a little disconcerting nonetheless.

Ed

And BTW, yes, a beautiful piece of work!

 

[Rocker]

Ed,

I have not done destructive testing, since, with the facilities then available to me, I was unable to destroy the joint. However I have tested a joint built in the same fashion. At a gtg of Australian Woodworking Forum members two years ago, we tested a a miter joint made in jarrah with twin keys. The jarrah's cross-section in the test joint was 35 x 40 mm (whereas the legs in my chair are 40 x 45 mm). In the testing, the single 35 x 40 mm joint supported the weight of four men without breaking. My chair has two (larger) joints to support the weight of one person, so I reckon that there is at least an 800% safety margin.

I intend to carry out some (hopefully) destructive testing next month at another gtg. I have built a zigzag frame similar to the frame of my zigzag dining chair, but with twin-keyed miter joints. I hope to be able to load up to eight men onto a board resting on this frame in order to see if their combined weight will break it. I suspect that, if the frame does break, the wood will rupture, rather than the joint; but we shall see.

Rocker

 

[Dan Clark]

Rocker

That's a gorgeous chair! I think it's your best so far.

Thanks for posting,

Dan.

 

[Rocker]

You can now download an article on how to build this rocker from my blog - see below. The seat cross-rails and the back rails are dominoed. The chair is not difficult to build if you have a well-equipped shop.

I have not been able to get this article published in woodworking magazines; I suspect that the editors are wary of being sued. Nevertheless, I am very confident that this chair will safely support the weight of any sitter who could fit between its arms. Destructive testing showed that it took a weight of over 800 lbs to break a a pair of twin-keyed miter joints made in timber with a smaller cross section than that used for this rocker. Moreover, it was the timber that broke rather than the joint itself. However, I would suggest that the chair needs to be made from a timber with similar properties to jarrah or maple; cherry or walnut might not be strong enough.

You can view a video of the destructive testing here: .

Rocker

 

[honeydoman]

I built this zigzag rocker based on a design idea proposed by a fellow member of the Australian Woodworking Forum.

Rocker

wow that is really nice, being from the late hippies days..... I guess we had a different meaning of a "zig-zag" rocker!!!  after all I was a zigzag rocker all the time.......

 

[Dave Ronyak]

Great film and test demo!!  I'm convinced that your Z-chair frame is more than strong enough for most anyone who could fit in it.

Dave R.

 

[Matthew Schenker]

Rocker,
Excellent -- and fun -- video showing the strength of the "zed" chair ("zee" chair for us Americans I suppose).

Looks like the testers were in more danger than the joinery!

Thanks again,
Matthew