I am 16 years old and attend St. Thomas High School in Pointe Claire, Québec. As a student in the International Baccalaureate program, I am required to complete a ‘personal project’ on a non-academic topic that is of interest to me. I have always enjoyed woodworking and design, so I decided to build a functional wooden bicycle. There was to be no metal used in its construction, only wood and glue. I wanted a project that would be a challenge.
Previously published in 2007.
This project came to mind as I was reflecting on the many stories my Opa, Case Vandersluis, told me about his adventures in Holland during World War II. Opa was roughly the age I am now when he had to build wooden wheels for his bicycle, as rubber was scarce during the war.
I wasn’t sure my wooden bicycle would actually work. I quickly realized the first pieces of the puzzle I needed to figure out were the chain and the sprockets (gears), since the design of all the other components depended on these.
I was mostly concerned that the wooden chain would break. I researched the strength of different types of wood and built jigs to test the stresses that each of the chain’s components would undergo during use. First, I used my weight (150 lb) to see if the wood could endure this amount of force. Then, my father would stand on the jig. I calculated that my dad’s weight would be twice the force each chain component would need to withstand. I made the specs high to ensure the chain and sprockets would work even if the wood had imperfections. During testing, I made adjustments to the chain’s components, and once I had it figured out, I realized that completing the project was within my grasp.
When I look back at the completed project, I realize that building the chain caused the most problems and also took the most time (nearly 40%). One of the biggest difficulties was drilling a hole in the spacers – hollowed-out, cylindrical pieces of wood that keep the two plates apart.
I attached a drill bit to our Shopsmith, which was in the lathe position, and used a chuck to hold the dowel. The job was difficult because the hole had to be drilled exactly in the center of the dowel. If it was even slightly off-center, the dowel would explode. However, it was only after I had successfully drilled some ten spacers that they began to explode. At first I thought something had loosened and the piece was no longer centered. I readjusted everything, but even after doing so, the pieces continued to explode. I then suspected that the drill bit might be getting dull. I was correct – as soon as I sharpened it, it drilled through nicely again.
Drilling the spacers alone took me pretty much an entire day. It was a labor-intensive job, since each hole had to be drilled separately and there were close to 100 pieces. It didn’t help that I made a small miscalculation and drilled nearly 1.5 times as many pieces as I needed!
Another challenge was drilling the holes into the blocks of rock maple that held the dowels in place for the frame. The difficult part was making sure all the holes were drilled in exactly the right position at the perfect angle to receive the dowels. This became even more difficult because some of the holes had to be drilled with compound angles. I used our Shopsmith and tilted the table to drill the angles accurately. To make sure the angles were correct, I placed a straight metal rod in the chuck and measured them using a simple school protractor.
The other challenge during this process was the fact that I did not want to buy new drill bits due to my tight budget. I could not sharpen the bits I was using because they were Forstner drill bits, so to prevent them from overheating and dulling, I drilled only a little at a time. I would remove the bit from the partially drilled hole, and while it was still turning I would take a bar of soap and rub it against its side to reduce the friction in the hole. This also cooled the bit slightly. I was lucky because the inexpensive set of Forstner drill bits lasted the entire project.
I decided to add a ratcheting system to the bicycle. This would allow me to ride down a hill without having to pedal. If it was a direct-drive bicycle, I would have to pedal at all times.
This piece was another difficult one to build because I was unsure how many fingers (the thin pieces sticking out of the center piece) it should have and how strong they should be. After designing all the pieces and determining the correct angles, I cut each one using a table saw, a jig saw and a bandsaw.
The design process took much longer than usual because I faced so many unknown challenges. My main concern was that the notch would not be big enough and the fingers would slip.
Thankfully, everything turned out fine. I cut the fingers with the wood grain, so that they would be as flexible as possible and, hopefully, not break. They needed to be flexible so that they would bend over each little notch when turning backwards.
After gluing all 18 fingers, I found that the ratcheting system was much too difficult to turn, so I weakened each piece using the Dremel, sanding off a thin layer of wood from each finger. Even after doing this, the system was still too difficult to turn, so I cut every second finger down. Afterwards, it turned smoothly, just as I wanted it to.
I finished the rest of the bicycle without too many problems.
In the future I hope to find another challenging woodworking project, but for now, I plan to focus on my schoolwork, my part-time job and sports.