Since my initial post about the midterm project, I have gone from low-fidelity cardboard laser cuts to a final product. When I wrote that first post I thought that the mid-term project would be a continuation of my Illustrator bike crank set homework with a slight ramp up in difficulty. I had the illustrator and laser cutter skills so combining those would be seamless. Countless hours in the OEDK later, I realize how much I underestimated this project. I now know that a project with 59 moving pieces and over 15 static pieces is a bear to take on, but I found myself really enjoying the work. I committed myself whole-heartedly to the project and was so happy when it finally started to all come together. Now that I’ve made some blanket statements about the project, I’ll get into the nitty gritty. Here is a photo of me almost done and happy at 3:30 am: As mentioned in my initial blog post about the mid-term project, I chose to continue the Bicycle Chain Machine project that I started when we were learning Illustrator. When I did the Illustrator homework I made as best judgements as I could about dimensions, but ultimately thought it would not matter if I was a little off because I would not being doing anything with the file later. When I revisited this file at the start of the mid-term I was pleased to find that the dimension I guessed were almost spot on. This was very helpful when trying to get off to a quick start. In the end, however, I ended up having to redo many parts of this as I began to use materials with different dimensions than the originals. Some of the parts, such as the base, I created on my own. I constantly had to go back and adjust Illustrator files and then cut during the course of this project. After my initial laser cut with cardboard, I went ahead and cut all the parts of my design except the stand with 0.25 3-ply wood. I did this so that I could start to build and see how things fit together. The main thing I needed to check was how the gear and chain links would all fit together. The chain was the main source of my woes during this project. After initially fitting it together on small sections of dowel, I tried placing it over the gears. The gears overlapped and could not rotate together, so I knew something had to be done to fix it. I went back to illustrator and checked the dimensions of everything and compared them to the book. The dimensions I used matched the book, so I went to the tips section to see if the author listed any advice. He stated that if the gears do not align, users should try sanding a chamfer onto the corners of the gears. I did this over the course of many passes of the dremel tool, constantly sanding and rechecking to see if the fit together better. This process took me a long time, but I finally realized that instead of trying to make 52 chain links fit a base that was too short for the gears I should just add 2 more chain links. This idea worked and I ran with it. As soon as this issue was resolved, another came up: how to keep a gap between inner chain links that the gear can slide though. Long story short, what I decided to was cut very small sections of brass pipes that fit into the center of the dowels to keep links apart. An image with schematics from my notebook illustrates this concept.  Cutting the brass tubing and assembling the chain took an incredibly long time, but after this was done it was relatively smooth sailing. From here I assembled my press-fit stand, added large dowels that everything rotates around , and added supports. After this I began the process of sanding and checking to start to get everything to align and fit together. Adding brass tubing increased the diameter of the dowels from 16/32″ to 17/32″, so I had to go back to illustrator and resize the gear to accommodate for this. Here is the bike chain when not connected in a loop: Here is a photo of cutting the brass tubing: In order to go from a rickety bike chain to a smoothly rotating one I sanded a chamfer onto the gears and the inner chain links. This decreased the chances of the gears getting caught on wobbly links. I also added tallow to the interface between wood spacer, dower, and gear. This helped create a smooth and quiet rotation. Here is a photo of the inner chamfer: Another big part of this project was making it look nice and post-processing it. The look I was going for was “steam punk,” which is kind of industrial-cool. Based on this I chose brass fittings as a nice compliment to the brown wood. I also used blue wood stain and linseed oil to alter the wood color. I also sanded the entire structure so as not to have rough edges. Here are some photos of this: Getting to the final product was very very tedious. When that “aha it’s working and done!” feeling came over me I realized how much pride I felt in my project. I think that fully immersing myself in the project made me get a lot more out it than I have with projects in other classes. Here is a video of the chain rotating: IMG_3728 Quick note: For this project I worked with Geetanjali and Paul. We did the projects largely on our own but used each other for consulting when we were stuck. It proved to be useful. Geetanjali and Paul are great people to work with and I’m glad we got to be around each other a lot. I also made sure to utilize my engineering journal during this project when planning different aspects of it. Here are scans of two of the pages: 0628_001 0629_001