This is my first instructable, so I hope it is clear, enjoyable, and inspirational! (give me your feedback on anything and I will revise) I re-use the same photo a lot because I don't have the bike in my possession right now to take others. Hopefully it is all clear anyway.
Goals for this tallbike:
-to be sufficiently tall, but can be easily dis-assembled, sort of like a folding bike. for fitting in a trunk or on a trunk mounted rack, or even in a rear passenger compartment if necessary.
-to ride as much like a "regular" bike as possible, specifically steering and pedalling.
-to be Relatively quick and easy to build with a minimum of welding, cutting, and custom fabrication.
-to be as strong and sturdy as any other tallbike building method
-to be disassemble-able with a minimum of tools and time
-a couple of similar-sized bikes from the trash or wherever. If you're reading this, I assume you probably have a bike pile. I used department store BMX frames because they have nice straight forks (more on that later), thick steel that is easy to weld, and they are pretty to easy to find in the trash.
-a stem with a bolt on plate that holds the handlebars, not the kind of stem with a pinch-bolt.
-a steel seatpost for the bottom frame. This gets welded to the top frame.
-a front hub. find a wheel that is taco'ed beyond repair or has a bunch of broken spokes, or even a broken spoke flange. Make sure it is not too small or big in diameter to clamp into the stem!
-standard bike tools like allen wrenches, adjustable crescents, chain breaker, pedal wrench, channel-lock pliers, etc
-a couple 4-foot long 2x4 pieces of lumber or other nice flat, straight pieces of lumber
-at least two 4" or 6" c-clamps, speedclamps, or something you can use to clamp to boards together.
-Welder. Whatever you have on hand that wont burn too hot. I used a $89 stick welder from Harbor Freight, some 1/16" rod, running at about 50Amps, plugged into regular AC outlet.
-Your other welding tools: helmet/goggles, gloves, chipping hammer
-Angle grinder, if you need/want to clean up welds.
Step 1: Headtubes
This building method eliminates welding in a longer head tube or chopping up forks and welding in a fork steerer extension. It also allows adjustments, dis-assembly, and helps during the rest of the build.