INTRODUCTION
We’ve all seen them around the OEDK: the ENGI 210 project known affectionately as “The Gear Project”. But what really is the gear project? What makes it so special and loved by many? Amelia and I set out to find the answers to these questions, not for ourselves, but for the many students who have asked these questions, but never found the answers. But to do this, we ourselves had to embark on a journey through the gears, through the depths of the OEDK, all the while getting lost in the gear sauce, to find the answers.
BIG STEP 1: GATE 1
2D Drawings
Gate 1 was the first threshold to getting to the root of the answers of the gear project. We first had to come up with an idea for our project and then create 2D drawings for our idea. Additionally, we had to know how it would function, hold itself together, and actuate. This part of the project took up the first week of the overall project time.
We first brainstormed ideas of what we could do for our model. We went from a globe model to a V8 engine, and eventually settled on something related to a solar system. However, we quickly realized that our first notion of modeling all the planets would be incredibly bulky and complicated (and just too hard), so we decided to instead just focus on a sun, earth, and moon model. We later found out that the name for what we were creating was an orrery. Initially, we planned to use mechanical movements #24 and #55, but that changed later in the process.
The next step was roughly sketching out our design, figuring out how the different parts would move and attach to everything. This initial idea used two two-stacks of planetary gears, one on top of the other to then have the sun rotate, the earth rotate around the sun and rotate about itself, and then have the moon rotate about the earth and about itself.
Once this process was complete, we then used Gear Generator to create SVG files for the planet gears and made Adobe Illustrator (ai) files. We also prepared ai files to test parts of our model. By this time, we had completed the first gate and moved into the second gate, and presented what we had created, all the while keeping in mind what our real goal was: finding answers.
BIG STEP 2: GATE 2
Low Fidelity Prototype
For Gate 2, we started to cut and assemble the files we worked on in gate one. This gate would take up the second week of the project time. We started constructing a low fidelity prototype out of cardboard. We also used hot glue to assemble the whole structure along with wooden dowels. But, once we put it together, we realized that the upper part would not work to spin the moon. There was no way to get rotation of the moon dowel with the current set-up we had, so we had to scrap our whole gear system and brainstorm different arrangements of gears.
This was our first failure and our first learning point: we realized that we should’ve spent more time on the setup instead of wasting time constructing something that wouldn’t work. If we used a modeling software to look at the workings, it would’ve shown us that the original design wouldn’t work.
Moving forward, we decided to try to replicate the way we set up the earth and sun in relation to each other, because they had the same motions we needed from the earth and moon. With this in mind, we ditched the planet gears and created new ai files to test in cardboard. Luckily, this new model worked out when we assembled it with the dowel/cardboard/hot glue setup. But, what we would find out later was that cardboard is much lighter than wood, our final material, and that it wouldn’t apply the same amount of torque and bending on the model.
BIG STEP 3: GATE 3
Mid Fidelity Prototype
For Gate 3, our goal was to get a more final assembly of the overall system with real wood during the third week of our project time. To do this, we needed to employ the laser cutter and Adobe Illustrator. Our general strategy was trying to assemble all the pieces in AI and then go to the laser cutter and print them out.
Our struggle with this is that the laser cutter was in very high demand due to all the other teams, so actually using the machine was hard sometimes. This is where Amelia and I felt could be an improvement to the project overall, stopping the reservation system, going to first come first serve, and only allowing laser cut usage when the files are already made. This way, there would be more efficient use of the device.
Throughout the process of printing and general assembly, there were a couple of sections of the model that were trickier than others. The first was that we had to mess around with the placement of the vertical gear on the earth/moon section so that it would actually function. The gear had to turn the gears above it, but the bar running over when it was rotating could not hit it. To remedy this, we created a thicker stack of gears for the upper gear such that the vertical gear would only catch the lower gears of the thick gear, and not the gears where the bar was resting. In this way we eventually reached a point where it would work. The second issue we found was that, like mentioned earlier, wood is heavier than cardboard, and the friction caused from the gears’ weight resting on each other (especially when moving further from the center) was making the model not turn. This was actually not addressed in this gate (it should’ve been), but we worked on that during the final week of our project.
Finally, we started figuring out how our supports would work now that we were more set on the setup of our gears. We decided to sandwich the central sun gears between two large circular plates so that the bar with the rest of the gears would be supported as it rotated around. Once we cut our initial design for this, we realized we needed to create a cutout for where the central sun gear and vertical gear were. We created this whole system in time to present it for gate three, but it was a close run thing. For this whole step, we used hot glue and wood glue for adhesives, and then wood for the gears and the dowels.
BIG STEP 4: ASSEMBLY OF FINAL PRODUCT
High Fidelity Prototype
FINAL ASSEMBLY!!! We thought we were close, but BOY were we wrong. For over 35 hours over 3 days, Amelia and I toiled away to find our answers. It was honestly pretty hard to maintain focus and drive at some points in the process, but we got through.
For the assembly of our final product, we added bearings and changed hole sizes for all the gears so that all the dowels would fit everything (hint: they didn’t). For the bearings, we made the holes 0.86 inches, and for the dowels, we made the holes 0.375 inches. We went through all the moving parts in our model to determine whether they had to be glued to the dowel or have a bearing.
Here are the highlights of what we did for the final assembly:
- Spray paint all pieces but the planets black, then go back through with a paintbrush and spray paint various colors (mostly white, some red, orange, blue, green, and gray) onto the paintbrush and then fleck the paint onto the pieces to create the illusion of space and stars
- For the planets, we spray painted the sun red, orange, and yellow; for the earth, we spray painted it green and blue; for the moon, we spray painted it gray and white
- Each gear was double stacked, so we would print double of each gear and then use wood glue to stick them on top of each other. Additionally, we did something similar for the bottom and top supporting rings
- We had a metal piece in the project that we used the waterjet cutter to manufacture; this was from an ai file, and used wood glue to glue this metal piece to another gear to beef it up a little because it was so thin
- For each dowel, the sizes of the dowels were too thick for the bearings we wanted to use, so we had to sand down dowels to the bearing size, which we accomplished by using a circular sander
- For attachment of the dowels to the gears, bearings, and supports, we used wood glue, epoxy, and hot glue
- We actually scrapped the whole upper gear system for the moon because we found that the weight from the gears and everything caused so much torque and weight on the lower gears that the whole system would not spin; additionally the vertical gear up there would not be strong enough to turn the two big gears we wanted it to, so we decided to unfortunately get rid of it
- We added little thin metal washers to the lowest gear on the base and the gear that rests on the upper supports; we found that this drastically decreased the friction and so decided to keep this implementation
- Finally, for the nameplate, we vinyl cut a sticker and then placed it on plate and spray painted over it, so that there was a clean nameplate
All these gave us our final submission. We are super proud of it and are happy withour result. But we also want to talk about some struggles and failures we went through:
- As mentioned before, the laser cutter reservation system was really tough
- The mismatch between the bearings and dowels made life really difficult because it was hard to linearize the size of the holes for the gears; if the bearing hole size and dowel size was the same, the project would run so much more smoothly
- Amelia and I definitely should’ve put in a little more work on the planning stages so that we didn’t have to spend so much time on the building and rebuilding stages
- We did have to scrap a whole section of the project, which was very disheartening; this decision was made because we were not going to get it to work in time, but we wish we could have made it work
- Finally, we wanted to have more dynamic planets that were 3D, but we just couldn’t seem to get the circle ratios to stack properly to get the notion of a sphere, but more of a pyramid
REFLECTION
Amelia and I at the end of the day did enjoy ourselves in this project. It was really neat to start with essentially nothing and then create something that is complicated. We laughed and we learned a lot about design, prototyping, iteration, and even a little about each other. In the end, we created something that we are both proud of and will definitely look on fondly in the future. We made it through a lot of struggles, late nights, roadblocks, laughing till we cried, and just general camaraderie.
But, I know what you’re thinking: Did you answer the questions you set out to answer?
The answer is…YES ABSOLUTELY. But, I think to find the answer for yourself, you will need to build your own gear project 🙂
COST BREAKDOWN
- 60 hours of work for $20/hour : $1200
- 6 Metal Washers: $3
- Plywood: ¼”x18”x24”, $7.50 per board, 6 boards: $45
- 1 Metal Aluminum Gear: $5
- ⅛”x12” Wooden Dowels, $0.07 per dowel, 3 Dowels: $0.21
- ⅜”x12” Wooden Dowels, $0.40 per dowel, 3 Dowels: $1.20
- Wood Glue, 1 Bottle: $10
- Hot Glue, 2 Sticks: $0.42 per stick, 2 sticks: $0.84
- Epoxy, 1 Tube: $5
- Spray Paint, 3 Cans: $30
- 2 Paint Brushes: $10
Total Cost: $1310.25
