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CvilleHokie605 OP t1_iynh1ne wrote

Reply to comment by 5degreenegativerake in ZipLine Post by CvilleHokie605

So would you drill a hole at say 7ft above the ground on the 6x6, run the wire through it and then anchor it a block of concrete on the ground? If it comes to that I guess I can go that direction but the presence of a wire going from the post to the ground with kids running around creates a possible injury risk.

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guccicolemane t1_iyo90wp wrote

no

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CvilleHokie605 OP t1_iyo95m1 wrote

very informative answer

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guccicolemane t1_iz0kgc8 wrote

googling zip line post and looking at the pictures would give you more help than making this post.

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CvilleHokie605 OP t1_iz12yc0 wrote

I've been looking at a lot of pictures and videos on this but wanted a discussion to go along with that to further my understanding of other's perspectives/solutions to this.

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guccicolemane t1_iz1gq8p wrote

https://i.pinimg.com/originals/59/6f/f6/596ff65c7f781fc1ec465c684993d452.jpg

https://i.pinimg.com/474x/f3/65/1e/f3651e10df09ebdf63acf701720416f9.jpg

or this https://everythingbackyard.net/wp-content/uploads/2017/10/dead-man-anchor.jpg

You dont want the cable to be stretched against a 90 degree corner on the wood post, so no hole in post with cable run through it. The cable elongates and retracts in size, it also stretches from bearing weight. Rubbing against the wood over time will deform it and weaken it. Putting it on an upside down pully as shown in one of the images above would work better. Or looping a chain around the post and then attaching to that with a hook and turn buckle would be what I prefer on my build. You tighten the turn buckle to account for any changes in cable length. It gets surprisingly smaller during colder times.

I prefer an A frame, you need 300lbs of concrete atleast in a 2ft radius of a foundation, buried about 2 feet of dirt so there is no movement. Two 2x4 kickers from the foundations out at a 45degree angle to the top of the 6x6 post.

Doing a single 6x6 post at a slight angle forwards with an pully at top, with the cable running over and behind, attaching to a 300+ lb concrete foundation buried a ways underground is the most efficient, I just dont like it for some reason.

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junkman21 t1_iynjmpu wrote

One way or another you will need to build a landing platform. And stairs. So, you can use the back two 6x6s as both a platform base and an anchor for the guy wires plus, possibly, flood lights.

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CvilleHokie605 OP t1_iynk1fn wrote

The start point doesn't need to be any higher so that doesn't need a landing platform (I'm in hill country so have plenty of fall already). I did plan to build a platform at the termination point though, but that has a tree so platform infrastructure doesn't give me anything I do not already have. Its the origination point that is tree-less.

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junkman21 t1_iynknif wrote

Oh, I see. This pole needs to be at the top. I'd still build a platform if I'm taking on a project like this. Even if it's only a platform 2 or 3 feet off the ground.

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CvilleHokie605 OP t1_iyo4iph wrote

What do you think about 4 6x6s glued and screwed together with the edges sanded round so as to not pinch the cable wrapped around them...

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junkman21 t1_iyoc3a4 wrote

I would think you would need through bolts, washers, and nuts if you want to go that route. You would also need to plane the two faces on each 6x6 that are getting glued for true adhesion.

Screws won't offer anything in terms of structural/shear strength. But I'm not a structural engineer and have never tried anything like this before.

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imnotsoho t1_iyp2v2t wrote

If you go to a professional lumber yard you can get larger beams, how about just 2 6x6 stacked in line with the cable? Guy wire to rear from top and brace in front with a small launch platform. Instead of wrapping the cable, drill a hole and terminate the cable on the uphill side. How are you going to avoid hitting the tree at the bottom?

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CvilleHokie605 OP t1_iyp6te2 wrote

My chosen system has a spring break. What is stronger I wonder: 4 to 6 ea of 2x12s thin side facing the termination point with the line wrapped around them like in the video another guy posted here, or two 6x6s in line with the line through them. Hmm

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5degreenegativerake t1_iyno9cc wrote

You can sleeve the cable in pvc pipe or something.

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tilhow2reddit t1_iyo80gj wrote

Iron Pipe would be my choice, a cable with that much tension on it could split PVC, and possibly split the post under load, and nobody wants that.

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5degreenegativerake t1_iyofyu3 wrote

I was talking about sleeving the guy wires so kids don’t clothesline themselves so bad. On the 6x6 I think I would just run the cable through a drilled hole near top.

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tilhow2reddit t1_iyo7v9s wrote

If you're going to run the cable through the 6x6 post like that I would drill an oversized hole and line it with a bit of iron pipe and run the cable through that, just to reduce the risk of the post splitting because of the cable/tension/etc. May even consider putting in some kind of brackets to reinforce that part of the post to keep it structurally sound.

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CvilleHokie605 OP t1_iyo81l2 wrote

What about 4 6x6s and run the line around them instead of through a single 6x6?

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tilhow2reddit t1_iyo8g6z wrote

I don't really see an issue there, but I'd probably still drill and all thread those posts together so they were acting as 1 solid piece, but that certainly seems like an option.

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CvilleHokie605 OP t1_iyo8ymg wrote

Oh yea, I would wood glue them together and then look for some kind of bolt to run through them to connect them all together, or an appropriate tie/mend plate or strong tie product I guess.

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