Upgraded Slackline A-Frames: New Design to Hold the Line Steady

My first set of Slackline A-Frames work fairly well. I’ve set them up and used them multiple times so far. However, one thing became clear after I started using them with people who do tricks – the ends of the Slackline are not held static where it passes over the A-Frame. This is an important feature to have: a steady, non-sliding line. I came up with a way to add the feature to my A-Frames.

IMG_2741First, I’ll describe the problem. As shown in the above photo of the original design, the Slackline passes over a piece of 1/2″ pipe. The pipe is 12″ long or so, and there is nothing to prevent the Slackline from sliding sideways (left to right). This happens predominantly when a slacker on the line does a move called “surfing”. They kick their legs out sideways and swing their feet back and forth in an oscillating motion. This action causes the Slackline to slide back and forth on the 12″ piece of pipe. The biggest downfall of this is that it abrades or melts the line just at the point where it crosses over the pipe. In addition, it makes for non-static ends on the Slackline. This is opposite of a tree-based Slackline, where the ends do not move left to right when in use, even while surfing.

The solution I came up with is fairly simple to implement. and can be made of parts from a hardware store. First, I made two of the U-brackets shown below. Each U-bracket is made from 1/2″ black iron pipe and some fittings. Each one uses the following parts:

  • four 90 degree elbows
  • two 4″ nipples (although any length under 6″ is OK)
  • one 3″ nipple
  • two 2″ nipples.

The only critical part is the horizontal 3″ nipple. The goal is to have 2″ (width of the Slackline) between the two 90 degree elbows once they are screwed onto the 3″ elbow. I was able to get the elbows to screw in 1/2″ on each end of the elbows, leaving 2″ for the Slackline. I used parts that I had laying around as well as pieces I bought at the store. Screw all the pieces together so they look like the picture below*.

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The second thing I did was drill two more holes in the top of each A-Frame to accommodate the U-bracket. These are 7/8″ diameter holes, to accept the 0.840″ outside diameter of 1/2″ black iron pipe. The holes go all the way through the plywood and the 2×6 legs – that way you can use longer nipples if you prefer (instead of the two 2″ nipples).

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The picture below shows the solution in use. The whole idea is to create a channel where the Slackline sits as it goes over the iron pipe. As you may notice, the channel I have created isn’t quite 2″ exactly in width. That is mostly because of the way black iron pipe is put together. Threads at the joints of black pipe are tapered. For industrial applications, fittings are screwed together until the tapered threads seal together. The joints are not an exact science, so the fittings don’t always end up completely seated, or even seated by the same amount. This is one flaw in my design, and it means I need to tighten my fittings a bit more (one or two turns, by the looks of it).

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In any case, the idea was to use off the shelf parts to create a steady point for the Slackline to pass over the A-Frame. Here is another picture of the setup in use.

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Of course, the length of all of the pieces of the U-brackets can be adjusted to fit your needs. As long as the Slackline clears the top of the A-Frame, things will be fine. I should probably shorten the 4″ nipple to reduce the leverage the U-bracket has on the A-Frame itself.

Hope you get the idea.

*You may have noticed that my 3″ nipple going horizontally in the U-bracket doesn’t quite look like a piece of black iron pipe. This is because I milled the 3″ nipple to remove the extra threads present once the 90 degree elbows are tightened to this nipple. You can get around this by wrapping the 3″ nipple with duct tape, or possibly by filing the threads down by hand. Otherwise, the threads will cut the Slackline and reduce its life.

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Chongo Mount

This past weekend, the kids over at Colorado School of Mines held a slackline festival. There were tons of slacklines set up, and people of all ages and skill levels participating in the fun! We were near this particular 150′ line, so I decided to practice my chongo mount. The video below shows one of my attempts. Although I did not walk far, I was mostly trying to mount the dang thing! Later in the day, I was able to walk 10 steps (at the opposite end of the line).

Catch Up

We were gone for a week, vacationing in Moab, UT. Didn’t get a chance to do any slackline while there, and since it had rained two days before we left for Moab, we hadn’t had a chance to slackline for one whole week. Back home, we set up the line and gave it a go. Good News! We got on the line and started walking right away! That is to say, we didn’t seem to lose much (if any) skill level. I was very impresses when my wife jumped up and walked 3 or 4 steps immediately! It was as if she hadn’t skipped a day of practice.

The one month mark (since our first steps on the line) passed us by last week. I hope that if anybody ever reads this, they realize that a person can make quite a bit of progress learning to slackline.

Progress Update

Slacked a bit on Thursday, but none yesterday (Friday) on account of high winds here all day. So, yesterday was a rest day. Set up today about 1p, and slacked for about an hour, taking turns with my wife. She was able to walk about 8 steps on the line today, so she is stoked! It really is fun seeing real progress every time we try it. I am now walking 8 or 10 steps backward, and I can move along the line at a better pace (no more stopping to catch my balance between every darn step!). Will set up tomorrow after lunch (and bowling).

Three weeks and we are moving right along!