Thursday, March 14, 2013

Recumbent Madness pt. 1

Various real life things like taxes and an attempt at finding a real job prevented me from posting last week (see "Dear Readers"), and for that I apologize and have written a ludicrously long post to make up for it.

After the successful proof of concept of the top level, it was time to begin constructing the lower, recumbent level of the Pariahcycle. So, I put on some metal, 

and, having never built even a normal bicycle in my life, got to work.

I began by laying it out on the shop floor in order to get a sense of the placement and scale of the parts I would need.
The result is that the upright portion is six feet from hub to hub, and the recumbent portion is ten feet from hub to hub.

I started by cutting the crank-set off of this thing so that the two parts could be used separately.

I was also using more of the horrible plumbing parts that I appear to have an endless supply of.
The ends of the tubing were too large of a diameter to be directly welded to the rear fork.

So I fired up the scary home-made forge that was built by a couple guys named Chris and Aaron. This involved turning on the gas with that red knob in the corner, then getting around to the front as quickly as possible to light it with a propane torch.

With that done, and with considerably less arm hair than I started the day with, I began shrinking the ends of the pipes down to make a better fit.

Then I did the same with the parts that connect to the middle crank, creating a thing that looked like this,

and one that looked like this.

Because of the way that the crank had to be cut off, I was left with this enormous gap.

To remedy this, I found a piece of scrap that was kind of the right shape, but which didn't fit very well.

Fortunately, thanks to some guys called Thomas, Hrayr and Karine, I was able to sort that out with a quickness.

Next, I cut the rear fork off this black BMX,
and began constructing a new back end for it that would connect to the low-profile frame I would have to build.

This was a little complicated.
I cut two pieces of tubing and beveled and shaped the ends so that they would fit snugly against the curved surfaces of the BMX bike. Once I'd done this, I welded them into this triangular shape.

Then I had to create a V-shaped component to match the angle of the parts I had built earlier.
In order to do this, I had to take two pieces of tubing and merge them to the diameter of one piece of tubing so that I could weld them to the triangular structure at an angle for strength.

Because the angle I had to cut out of these pipes was so acute, the chop-saw didn't have a setting for it. As a result, I was forced to cut it out with an angle-grinder.
It turned out pretty sloppy, and required a huge nasty weld that is going to have to be in an unfortunately visible place.

The next thing I had to do was straighten everything out so I could tack weld it all together. I didn't really have a straight-edge that was long enough to be of any use, but that didn't matter because the frame had nothing to use as a reference point anyway. For this reason I resorted to just sighting along it, straightening everything out by eye. Once I thought I had it straight enough I tacked it all together, then stood back and looked at my work.

I had forgotten to double-check it.
It's probably hard to tell from this picture, but it was quite crooked.

I had to cut it apart and try something else.
On my next try, I clamped a long piece of rectangular tubing I had found to it, and tack-welded it again.

There was no really good place to do the clamping however, so it turned out crooked a second time.

I was again forced to cut it apart.
At Kai's suggestion I used string and C-clamps to stretch a line along which I could sight the frame. This worked great (helpful bastard), allowing me to weld it together for the third and final time.

With that, the frame was completed.
All ten feet of it.

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