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I want to create a play structure for a super swing. A super swing is like a tire swing in that it can travel in all directions and spin like crazy. I used to have it on a tree branch but we moved to a house with no suitable limbs.

I was planning on using two 6x6x12 vertical posts set 2 feet deep in concrete with one 6x6x16 cross bar. I was going to use two diaginal pieces in the interior to help with any bowing.

I am mostly worried that the cross bar will break from the forces of the swing. I can set the posts deeper to reduce the forces (or if the depth is insufficient), but I would like to maintain the 10 feet above ground if possible.

Any other advice or suggestions appreciated.

  • I would use an A frame on any type of swing. 6×6 × 16 is a long span and maybe fine with a couple of kids. some of today's lumber I would want to hand select #2 or better to make sure to get a beam that could do the job. – Ed Beal Feb 26 '18 at 3:27
  • 2 feet is not deep enough, even in concrete. It'll loosen and wobble before you know it. You may need twice that, depending on the soil. – isherwood Feb 26 '18 at 5:16
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A swing frame must be very rigid or the energy put into the swing gets sapped, causing it to quickly lose momentum. This is why you rarely see swings on posts. I'd stick with a proven design, the A frame. If you really must use vertical posts, go at least 3 feet down. With 10 feet above ground the torque will be quite strong.

Interior diagonal braces effectively reduce your beam span. You could easily cut 3 feet from each side, leaving 10. I'd trust a select 6x6 to span that just fine. The braces must be securely fastened, though. I'd consider mortising them into the beam and posts.

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Use a metal pipe for a crossbar and the legs, of sufficient strength to avoid bending or breaking. I don't know where you live, but if it is in a freezing climate, you might want to go 30" into the earth to avoid frost heave. You say: " I was going to use two diagonal pieces in the interior to help with any bowing."Wouldn't that be in the way of the swing?

  • What size pipe do you propose would span 16 feet? – isherwood Feb 26 '18 at 5:13
  • @ isherwood. I'm not a structural engineer, but I would consult one to answer your question, and for safety sake. – user81998 Feb 26 '18 at 6:07

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