Burning Man 2013 Honorarium Project / Impossible Triangle Now Made Possible
EmailRSS

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.