5 Boro Bike Tour Tandem Trike: Accidents Will Happen
The task for the weekend was to get the rear wheel fork on the trike. The weather had different plans. Constant rain was on order for Saturday, threatening to render my workshop (back porch) a soggy useless mess. Luckily I remembered that I had a patio umbrella stored away. Once I dug that out and set it up, I had a perfectly serviceable area in which to work.
I started by fabricating the rear dropouts in Atomic Zombie style with my grinder and cutoff wheel. Well, not in completely A/Z style. I did use a drill press to make the 12mm hole for the wheel axle. The hole was actually 1/2″ as I don’t have metric drill bits, but we’re talking 12.7mm versus 12mm-close enough to get the job done. It took a little over an hour to make the dropouts. These aren’t the highest quality parts I’ve ever made, but they are perfectly functional. I intend to clean them up a bit before painting the trike.
After making the dropouts went so smoothly I was cruising on the momentum. It was time to tack the dropouts to the rear fork legs. If you recall, I already made those as a way of practicing my welding. It would turn out that I would have a lot of welding practice over the weekend.
I aligned the dropouts on the fork legs and tacked them. it was time to check how they fit on the wheel. They fit great! But wait…why are the openings facing that way? They should be down…Urrgh! I tacked the dropouts on backward.
There was only one thing to do. Outside to the grinder and break the weld. I cleaned up the parts, flipped the dropouts around, made sure they were aligned, and tacked them in place. Now I was ready to try them on the wheel again.
Success! The dropouts face the same direction and the fork legs are even. It was time to mock up the rear fork on the frame.
I set up the frame on buckets at the height specified in the plans. Believe it or not, using buckets to get the right height is the method prescribed in the plans. If you buy a set of Atomic Zombie plans, you’ll see that they are very practical in their approach to building. It is standard for the plans to specify commonly available objects to assist with the building process. Where a typical plan would have you build a jig for one thing or another, Atomic Zombie has you using whatever you have lying around to best effect.
In the spirit of using what I had, I pulled out some magnets to hold the fork legs in place. That worked really well. If I was using a standard tire I could just angle the fork legs until they touched the frame and that would set the fork leg angle. However, my tire is 2.75″ wide so I knew I’d have to add spacers to the frame in order to get the fork legs to clear the tire. I also wanted enough space to add a fender at some point. Using 2 magnets on either side of the frame seemed to add just the right amount of space. As you can see in the photos, it looked pretty good.
During all of that sighting down the frame to get the rear wheel aligned I noticed something. It looked like the front boom was a little crooked. It looked like it was pushed off center by about 3/8″.
Every object has an accuracy tolerance because perfection just isn’t possible. I don’t expect perfection but a project should pass the “looks right” test. Generally speaking, an acceptable level of quality is where imperfections may be measurable by instruments, but not detectable by eye at a typical viewing distance. Standing in front of the trike frame I should not notice any misalignment. I did.
Well, this just couldn’t stand. It wasn’t just a question of aesthetics. Yes, it looked bad but the steering booms and wheel alignment would also be affected by a crooked frame. There was just one thing to do – cut the frame apart and re-weld it straight. That would be the task for Sunday.
First thing, I set about grinding down the welds before cutting the frame apart. I learned a couple of things. First, my welds are plenty adequate. My cheap little welder is up to the task of creating strong welds and my technique isn’t so bad. I guess I remember more about welding than I thought. You can’t completely judge a weld by how it looks on the surface. Second, I need to always check my cuts. Despite having taken a lot of time setting up my chop saw, I found the source of the misalignment to be a cut that wasn’t square.
I cleaned everything up with the flap disc and went through the frame alignment process to mark the cut. This time I cut the tube with a cutoff disc, being extremely careful and slow. I double checked my cuts for square and used a file to dress the edge. When I clamped the halves of the frame together, I used steel angle on both sides to make sure the frame stayed where it should. I welded up the frame and took my own advice about leaving the tight angle un-welded.
The frame is now dead straight and I can continue on with peace of mind. It’s inevitable that these kinds of things happen during a build, especially when one is rushing. The main thing is that the issues get resolved, especially when they effect quality. Even though I am building this trike for a specific event, I’m building it to last. After the 5 Boro Bike Tour, there are countless adventures waiting for this trike. It has to be up to the job.