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  1. #1
    Senior Member Cabmanhang's Avatar
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    DIY Tensahedron -- 3/4" emt conduit longest length?

    Does anyone have experience with maxing out the length of their diy tensa poles?

    Anybody experience failure on 3/4 emt at any particular length.

    I may be asking a question that has already been answered, but in my searching I haven't found it.

    I see the results vary from under 8ft to 9ft 6inch.

    Is there any reason I can't leave mine a full ten feet?

    Any help is greatly appreciated and kudos to all of the great threads that have been created showing how to diy a tensa.

    Latherdome, you are awesome for supporting the diy aspect of your clever product!
    "If we lose the forests, we lose our only instructors. People must see these forests and wilderness as the greatest educational system that we have on the planet. If we lose all the universities in the world, then we would lose nothing. But If we lose the forests, we lose everything." -- Bill Mollison

  2. #2
    cougarmeat's Avatar
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    I could be all wet here but recall that with trees, the further apart the trees, the higher the suspension has to be in order to maintain the best angle. So longer poles could just make the setup more complicated. One goal is to use the minimum amount of material that will do the job. It seems there is a "balancing act" going on in setting up the stand - setting it and the best angle, with the base the required distance apart and hammock positioned so the support poles are being hit, etc. Once that golden setup is achieved, you could look at what is excess and remove it.

    So you could leave yours at 10 ft, but you might find yourself crossing them at a point shorter than at the ends. So for storage and carry weight, you might cut off the excess.
    In order to see what few have seen, you must go where few have gone. And DO what few have done.

  3. #3
    cmc4free's Avatar
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    Longer poles means more bending moment, with the peak stress at the center of the pole. You didn't mention your weight, and I don't have any empirical numbers to list anyway, but if you're reasonably lightweight, you could probably use 3/4 EMT at the full 10' length. I'd recommend you don't segment the poles if you want them to be that long, but if you do segment, I'd break them into thirds rather than in half, so the center of the assembled pole is solid, not a joint. While you're still building confidence, it would be wise to hang over some padded material and avoid having the hammock too high above ground.

    Before the commercial Tensa4 was released, I played with 3/4 EMT and didn't want to cut them, preserving their versatility for use on future projects. However, I also didn't suspend the hammock from the very ends of the poles. The poles crossed at the apex probably a foot or more from the ends of the poles, so effectively I was only using 8.5' - 9' poles even though they were uncut 10' lengths. I didn't drill any holes either - I used lashings, and tightened hose clamps onto the EMT to keep the lashings from sliding up or down the conduit.

    Using 10' poles would give you some potential advantages, like being able to easily set up a 12' tarp, if that's what you have. With the commercial version, using a tarp longer than 11' requires either some compromise, creative rigging, or the addition of the tarp extension poles.

    With longer poles, you can still achieve the desired 30ish degree hang angle and an appropriate sit height above ground. It just involves tinkering with things like your hammock suspension lengths, stand ridgeline length (if you use a ridgeline on the stand), and stand baseline length.
    Last edited by cmc4free; 09-13-2019 at 13:19.

  4. #4
    Senior Member Cabmanhang's Avatar
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    Quote Originally Posted by cougarmeat View Post
    I could be all wet here but recall that with trees, the further apart the trees, the higher the suspension has to be in order to maintain the best angle. So longer poles could just make the setup more complicated. One goal is to use the minimum amount of material that will do the job. It seems there is a "balancing act" going on in setting up the stand - setting it and the best angle, with the base the required distance apart and hammock positioned so the support poles are being hit, etc. Once that golden setup is achieved, you could look at what is excess and remove it.

    So you could leave yours at 10 ft, but you might find yourself crossing them at a point shorter than at the ends. So for storage and carry weight, you might cut off the excess.
    Excellent thing to consider about the height complicating matters. Only one way to find out..

    Quote Originally Posted by cmc4free View Post
    Longer poles means more bending moment, with the peak stress at the center of the pole. You didn't mention your weight, and I don't have any empirical numbers to list anyway, but if you're reasonably lightweight, you could probably use 3/4 EMT at the full 10' length. I'd recommend you don't segment the poles if you want them to be that long, but if you do segment, I'd break them into thirds rather than in half, so the center of the assembled pole is solid, not a joint. While you're still building confidence, it would be wise to hang over some padded material and avoid having the hammock too high above ground.

    Before the commercial Tensa4 was released, I played with 3/4 EMT and didn't want to cut them, preserving their versatility for use on future projects. However, I also didn't suspend the hammock from the very ends of the poles. The poles crossed at the apex probably a foot or more from the ends of the poles, so effectively I was only using 8.5' - 9' poles even though they were uncut 10' lengths. I didn't drill any holes either - I used lashings, and tightened hose clamps onto the EMT to keep the lashings from sliding up or down the conduit.

    Using 10' poles would give you some potential advantages, like being able to easily set up a 12' tarp, if that's what you have. With the commercial version, using a tarp longer than 11' requires either some compromise, creative rigging, or the addition of the tarp extension poles.

    With longer poles, you can still achieve the desired 30ish degree hang angle and an appropriate sit height above ground. It just involves tinkering with things like your hammock suspension lengths, stand ridgeline length (if you use a ridgeline on the stand), and stand baseline length.
    Sound logic. Thanks for the feedback. I do want to accommodate a 12ft tarp. I think I will just go full length and take my chances. I can always work it down in length and just redrill the top holes. In Carpentry we say "they don't make board stretchers, so ease up on the cut."

  5. #5
    cmc4free's Avatar
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    Quote Originally Posted by Cabmanhang View Post
    Sound logic. Thanks for the feedback. I do want to accommodate a 12ft tarp. I think I will just go full length and take my chances. I can always work it down in length and just redrill the top holes. In Carpentry we say "they don't make board stretchers, so ease up on the cut."
    Exactly right - you can always make them shorter, but....

    For reference, the commercial version has poles that are just about 8'6" long and the holes are drilled less than 2" from the ends. A 12' tarp will not fit on that setup unless you really compromise the hammock sit height and the height of the tarp ridgeline above the ground by splaying the ends of the stand far apart. Well, actually a 12' tarp can fit, but you have to do something more creative like pull one corner of the tarp past the apex of the stand and stake it to the ground, sort of like this photo from Crazytown3.


  6. #6
    Senior Member Cabmanhang's Avatar
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    1A2FF85C-4F60-4193-9903-D2591286A1AC.jpg

    Full ten foot lengths work fine. Fits a 12ft tarp nicely.

  7. #7
    Senior Member BigE94's Avatar
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    Quote Originally Posted by Cabmanhang View Post
    1A2FF85C-4F60-4193-9903-D2591286A1AC.jpg

    Full ten foot lengths work fine. Fits a 12ft tarp nicely.
    Whats your weight using the 10' lengths?
    I would rather be in the woods... my dog would rather be in the pool. My wife thinks we are both nuts.

  8. #8
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    A bit of an aside, but are you using regular pegs for holding down the end. I couldn't tell. The big plastic ground screw looks like an ideal thing to get. Tough but easy in.

  9. #9
    Senior Member Cabmanhang's Avatar
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    Regular aluminum + stakes. Holding fine. I would recommend a stronger stake though. Just in case. I also have a guy line on the head end to keep me from collapsing the tensa on myself.

    The tarp is also tied to stakes in the ground. Probably best for the tarp to have it's own stakes, but at the foot end I have it coupled to the same stake. Just testing the minimums, but this is working in my sandy soil.

  10. #10
    My stand is 10' EMT.
    I weigh 190#.
    No problems.

    Sent from my Nexus 5X using Tapatalk

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