Burning Man 2013 Honorarium Project / Impossible Triangle Now Made Possible
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The Chinatown Exit

For some reason I’m a little too excited about the fact that our base is made out of I-93.  I was getting worried that there might be a bridge out there missing a cross beam or two, but we noticed today that there’s an exit number on here.

According to Wikipedia, Exit 22 is the old Chinatown exit, now, post-big dig, named exit 20.  As we all know, the big dig was largely funded by federal taxpayers, and it is clear that the big dig paid for this beam’s removal.  The way I see it, this art project is the west coast’s cut of the big dig action.

Steel Footer

The containers need to load in nine days, and we are sprinting.  No major impediments, but there’s a lot of execution left.

One critical part of the design is the base.  We didn’t want to have dangerous guy wires interfering with the piece, so we designed a heavy-ass base for it.  Actually, “we” designed a reasonably lightweight base, but Surly just fell in love with those chunks of ’93.  Once he had them where he wanted them, he turned the over to Shop Monkey for cleanup.

It’s coming together pretty will.  The vertices are made out of an old gas tank, a larger version of the kind used to make the bells you ring when you enter the event.  There should be some good hippie BS there.  ”The bell I ran as a virgin has been symbolically cut into pieces and made the foundation of this work.”

The tank’s wall is only about 5/16, and the flanges are 3/8 and 1/2″, which makes them considerably beefier.  We’ll reinfoce the tops to stiffen them up, but I also like that they will bend first, letting the base move and settle  We’ll still have 3800 lbf anchors on each part of the long extensions.

That lower arm is looking pretty good all powder coated, isn’t it?

Here’s the layout:

Taking I-93 to Burning Man

Yesterday, a flatbed arrived with some I-beams for our base.  Although the upper part of the design needed to be made from new materials, we wanted to reclaim materials for the base.  Fortunately, the junkyard around the corner had a few old pieces of I-93 we could use.  They were a little heavier than anticipated, but we are buying them at scrap rates, and we can sell them back if we ever get this thing permanently installed someplace.  Here, Leonid inspects the delivery with glee.

Surly does things with a forklift you wouldn’t imagine.  It’s kind of like his hydraulic left hand.  Once again, Google automatically made made a little ditty of the procedure for attaching a horizontal band saw to one of these with the forklift.

Have you every seen this guy any happier?

When it all goes together, it’s supposed to look something like this:

The cylinders in the vertices will be made from a old welding gas cylinder.

 

Two Arms

Tonight involved two fork lifts, and lot of “you’re doing it wrong,” 5/8ths flange bolts tossed to the floor over and over, a few ladders, various types of hoists and straps, two scale models of the assembled piece, and sprinkler pipe, improperly installed Romex, at least three different welders, and the ceiling itself coming dangerously close to tragedy.  The water cooler didn’t come out very well at all, and various boxes of different colored fasteners have been scattered into nether regions under desks that are actually immune to magnetism.  Entire piles of I think this belongs to so-and-so have been shuffled so that the true owner can never be identified.

Keep in mind I designed the thing to be just a few inches short of Surly’s ceiling.  I mean, we wanted to make it as big as we could.  That ceiling seemed really far up there.  Pretty cool that Surly can drive a forklift under it, though.  Actually, I have now seen a new kind of forklift art that will keep me up a night for weeks.

Yes, that is a bolt of lightning come straight from your deity of choice to the piece.  Although we appreciate being anointed in plasma, that won’t happen when we close the circuit by adding the third arm.  Also notice the gallon of lacquer thinner with the box of combustibles as a cap.

Standing on a welding table, you can almost see it start to work.

I told Surly that we had to assemble the last arm in place, due to tolerance stack-up and that any errors in length would turn into a problem in all three axes around the piece.  The first thing I did when we got it standing up was to grab the test arm and check the fit.  It was about 1/8th long, which is well well well within the happiest place it could be.

We Have an Arm

Apparently Google thought that it could turn balancing into dancing a jig.  They appear to be right, although it needs a soundtrack.  Proud to be wearing a SpaceClaim shirt, even if I’m filthy!

Surly always the first pass welding.  Dorothy has been filling in some areas and some gaps.  In fact, if you look closely in the above, you can see that beam “1o’=” hasn’t been welded on its underside and there’s a a totally acceptable gap.   In case I didn’t mention it before, our tolerance is +0 / -1/8″.

I’m pretty sure those welds are Surly’s.  They’ll require some finishing, but I’m happy with the coverage.

This Might Actually Work

Things are starting to come together chez Surly.  There’s been a lot of processing on the beams.  Here Amber seems genuinely pleased with the business that 1.5″ roughing mill delivers.

Although Surly has plenty of bench space, Dorothy is more comfortable deburring the plasma cut plates from  the floor:

Here’s how the arm beams work.  Jacob used the wood router at Artisans’ to lay down a template:

We had to outsource the beam bending for this size tubing, but we gave them a template based on the template itself.

Once the corner cubes are placed just where they need to be, the bent arms get fitted:

Notice we took some scrap 3/8ths and made some fixtures to help position the arms on the flanges:

Once the bent arms were in place, we could see if the beams and all the crazy sticker business actually worked.  Here are the beams taped roughly into place:

Surly then adjusted everything to the right vertices and sent me this cell phone photo of it all welded!

Now, another arm and we get to see if it all lines up!  Frankly, it’s a miracle those arms worked out as well as they did.

 

Tube Time

This past weekend was beam making time.  After five iterations, I finally came up with a process that outputted stickers that were properly sized and aligned.

Once carefully applied to the beams, we rough cut the long end of the already rough cut beam to clear away material for the more detailed cuts.  Here Amber demonstrates the proper use of safety glasses while operating the horizontal band saw:

Notice that the stickers are applied with a wrap of packing tape to protect them during manufacturing operations.  The challenge is that the fixture for the beams on the mill is tight, so any wrinkles in the tape wreak havoc.

Next step is to rough cut the angles.  More than half of the angles are greater than 45°, so standard miter saws won’t cut it. The dark lines running axially are supposed to line up vertically to help eyeball the cut from the ellipse representing the cut itself.  It’s very hard to get the bottom right, but Damon did a great job on these:

We found it easier to notch the beams after a clean up on the sander, where we made them dimensionally accurate apart from the notch.  Here they are after the notch, where they nominally deserve to fit on the bent arm beams.  Note that our tolerance is +0/-0.125, and these are sized to just mostly remove the blue line.  You can also see that the enormous toothed endmill leaves a rougher, but cooler finish than the sander.

Next, these beams need to get fit on the arms, and the stickers help by naming the beams, their handedness, and which side is which.  We are supposed to get the curved arm beams from the benders on Tuesday, after which we can make the arms and see if this thing actually deserves to fit together.  The beams will probably require a little hand fitting on the arms, after which the will get prepped and welded.