Check it out! Wheels!

There's a red support post holding it up, because the wheels aren't attached yet. Attaching the wheels is going to be a delicate operation to keep everything lined up and balanced, but here is the trike (less the seat), it's first real appearance.

Clever Solutions to Stupid Mistakes

#1 Rear Wheel Misalignment
Okay, this is not so much of a clever solution. It's more a stupid solution to a stupid mistake.

The rear wheel must, of course, be mounted with the gears on the correct side of the bike, so it lines up with the gears on the crank set.

Once I did that, my problem went away.

#2 Chinese Crap
This solution is more clever. It turns out that the biggest problem with the bearing set was that the parts had been tightened too much. Once I loosened appropriate nuts, the sensation of riding on a cog railway went away.

Okay, a better solution would be to throw the Chinese crap away and buy real bike parts. This is a poor man's clever solution.

Stupid Mistakes #2

I did it! I bought the kid bikes from which I will harvest the front forks. Walmart kid bikes are much cheaper than buying the parts from even online bike shops, and who knows? I could even put the rear section together with the front wheel from the mountain bike and make a delta trike later.

I got what I paid for, which is Chinese crap. The steering and the axle turn like in place of ball bearings, they have twenty-sided dice. If you apply a little force, they go bump-bump-bump, about 3-4 bumps to go through an eighth of an arc. Swell.

Stupid Mistakes #1

Dang!

Anyone else trying this, learn from my supid mistakes. When attaching the rear fork into the bike frame, do it with the wheel in the fork. I just put the wheel into the fork, and it's all but impossible to keep it from rubbing up against either the bamboo, the brake, or both.

Now I have to cut off the rear fork and put it back on again.

More Steering

Now what I need to decide is how to mount the steering mechanism. Options:

1. The easy way, relatively speaking, is to cut out the steering system from the old bike and affix it under the seat. Unfortunately, the old bike's head is longer than the space where it needs to go, so this is out.
2. I could cut off the top of the old bike's head. This would allow me a solid steel cylinder to put the yoke into, and a system of bearings to make it turn easily. I would need to devise my own way to keep the yoke from pulling up out of the head, and I would lose some of the anti-wobble effect of the longer head. Not sure the impact of losing the bottom system of bearings, beyond these two. Also, the yoke is too long for the space, and would also have to be shortened.
3. A variation of # 2: I could cut out the middle of the head, and attach top and bottom together. Would give me the bottom bearings, but would make the head a weak-point. All I could do to join them would be to apply epoxy, and this might also compromise the free turn of the handlebars.
4. Find a smaller head. The main problem here is the hassle and cost.
5. I could attach the handlebars to a perpendicular pole, then put a simple pin through the pole, and be done with it. Say, use a short bolt, one of those quarter-inch ones that has a length without threads. There'd be more wobble than either of the above, and it wouldn't have the bearings to turn so nicely around, so precision, high-performance steering is out. But it's by far the simplest.

Steering

There are two basic formats for steering that I can think of, illustrated in the diagram above. The green bar is the handlebar, the blue dots are joints, the red are steering bars. The triangle represents the stem of the yoke that turns the wheels, in black. The handlebar turns about its center, not marked.

The first thing I think about them is that the push-pull format seems to work best when the steering is significantly behind the wheels, although I have seen other designs that use the lateral design from behind, and use a bent bar (the long red one in my diagram) to reach the wheels.

I think the real difference is the travel, how far you turn the handles to turn the wheels. I think the push-pull method would make the wheels turn quickly with very little motion of the handlebar, not a good thing. In the lateral method, the shorter the little bar (red) that connects the handlebar with the long red bar, the longer the travel of the handlebars.

It's also the method I've seen on pro trikes.

A Place to Sit

The crank is secure. Secure enough that I can sit on the bike, put my feet and the weight of my legs on the pedals, and pedal. The first of many tests.

Which brings me to the place of making a more comfortable place to sit. I have a fine plan to make the seat, two pairs of poles joined at an obtuse angle, and joined by two parallel poles perpendicularly, and a back and seat made of nylon. But the big questions are where to put it, and exactly how wide an angle, and how large must the seat and back be.

I answered the last question by measuring some chairs and the placement of my butt on them. I didn't want to make the seat too large, as I didn't want my pumping legs to chafe agaisnt a seat edge. I want it under by butt, not my legs. I answered the second question by sitting against a board and reclining it to a good angle, then replicating the angle.

I thought the last question would be the easiest, because I could simply put the seat on and secure it. But I find that the placement of the seat is dictated by the placement of the pedals and length of my legs, and I fear that the place dictated is so far forward as to make the bike front-heavy. Depending on the weight of the rear-mounted engine, during a hard stop it could try to do a nice face-plant on the pavement.

I was imagining the only solution would be to cut off the nose and shorten it, but while I was typing it occurred to me it would be far easier, and involve less threat of weakening the structure, to cut off the crossbar and move it forward. Problem solved, thanks for listening.