By: Nicole Mitchell and Madison Nasteff

Note: Both blogs and mechanisms were created as a joint effort among both teammates

For our midterm project, we were tasked with creating a device based off of a movement from 507 Mechanical Movements. We were to use our skills in plasma and laser cutting to assemble a device that could be operated by every day users in the OEDK.

During our Illustrator Assignment, Madison recreated Movement #69 in Adobe Illustrator. This movement has one small gear that, for every time it rotates, rotates one tooth of a larger gear. We decided we would pursue this design because it was already created digitally and we would be able to get creative with the stand since it was a simple 2-gear mechanism. We did have to touch up the design in Illustrator because the gears were not meshing well, but shown below is our final illustrator design for the gear system including the OEDK base. We also had to think about how we would create the crank. We opted for a simple circular crank to be attached to the smaller gear. These pieces are also shown below:

Final Gears and Base

Pieces for Crank

 

For our first iteration, we tried to use cardboard for the gears, but this didn’t work because the gears did not mesh well due to the gaps in the cardboard. For this reason, we chose to do a hybrid between a low- and medium-fidelity prototype. For this prototype, we determined the best course of action would be to cut the gears out of wood to show a proof of concept with a simple square cardboard backing, shown here: –>

This prototype served as a great proof of concept, and we decided it would be appropriate to move on to a higher fidelity device. Unfortunately, as we scaled up the design, we experienced some problems. The gears were not meshing as well as they were at the start. We had to do a bit of editing to the Illustrator file for the larger device. We redesigned a bit of the gear, until we came to the drawing shown previously, and it ended up working well. For our final gears, we decided to use acrylic. This would allow the OEDK letters to be more visible, and the overall aesthetics of the device to be improved. We had a bit of trouble laser cutting the acrylic, but after a few passes on low speed/high power, we got the gear to punch out of the acrylic, and it made for a really nice looking gear.

For the base of our high-fidelity model, we plasma cut it out of steel. At this point, we actually had to scale down our base pretty significantly because we did not have enough material to create a base of the size we had originally planned. Luckily, the gear we had cut still fit on our smaller base. After cutting, we removed the dross on the back side of the piece using the belt sander in the machine shop. While this removed the dross on the outer edges, we weren’t able to completely clean the inner edges. To file down the inner edges, we used a hand-held orbital sander. We liked the look of the finish, so we decided to even out and clean up the surface by running the orbital sander over both sides of the steel plate. We polished it with an orbital sander until it had a nice shine and even “brush”-like strokes. We drilled the holes for the axes, and then used the press brake to get the correct angle for the base.

After cutting the acrylic, the next step was to assemble the device. We used wooden dowels, wood spacers, and acrylic pieces for the crank. To attach the pieces, we started out using hot glue, but we quickly realized that it caused too much friction in the device. It took several iterations to make the device turn smoothly, and we eventually found super glue to be the best adhesive. We also spent a lot of time sanding the wooden dowels until we were satisfied with the result and it was smooth enough to pass what we called the “Wettergreen Wiggle Test.” The final device is shown below, and a video can be seen at the bottom of this post.

Final Product: Front View

 

FINAL PRODUCT: Back VIEW

Overall, we were very satisfied with the result. The device runs very smoothly and aesthetically is just what we were looking for: something professional looking and very clean. Throughout this project, we learned that oftentimes it is worth it to take something apart and reiterate it to make it exactly what you want. When assembling, we ended up taking the device apart several times, but through these many iterations, we were extremely pleased with the final result.

The biggest challenge in creating this machine was thinking about the small aspects that can make a huge difference, such as what type of glue to use or how much to sand the dowels. If you sand too much, there will be too much wiggle. But, if you don’t sand enough, the dowel will not rotate smoothly. We had to continuously modify our device to make sure that we found the perfect balances. While this was frustrating at times, the end result is something we are very proud of, and it all seemed to be worth it.