I signed up for the summer ME 13 Introduction to Mechanical Prototyping class a while back thinking that it would be a great opportunity to pick up some useful design skills. Since I am a prospective Electrical Engineering student, I would not have time to take the class during the academic year. There are demos for different machines each week, and we learn skills to build this cool moving trophy at the end for our final project. I promise it is more sophisticated than what I make it out to be.
Anyways, I was able to get in the shop a day before class started because I needed to make a small apparatus for tensile testing for my SURF project. Essentially, I needed to cut down two aluminum blocks and put four matching holes through them, then attach the blocks to an existing apparatus. I assumed that the process would take roughly 30 minutes, but it ended up eating up my whole day. I had completely underestimated the amount of time it takes to tap, thread, and what not, all for a single hole. It took so long even though I had a grad student perform all the manual labor for me!
For our first class, we learned how to use a Johnson saw, and a lathe. We cut some aluminum rods, then shaped, taped and threaded the ends. I have a funny and sad story to tell about this experience…
While using the lathe, I was moving the blade in the Y direction and I got confused between clockwise and counterclockwise on the wheel. I almost lobed off an entire end of the rod that I had so painstakingly shaped. Thankfully I caught myself, but there is now a divot in one end. Now, a near miss is not as bad as an ACTUAL miss.
The final step is to thread the hole we had tapped. Well the thing about threading is that it can only be done once, otherwise the threads will become messed up. I was so eager to finish up (I was getting hangry) that I only threaded the hole half-way. Since I can’t go back in with the tool, it meant that I now need to re-do the whole part. To sum up the experience:
On the bright side, I can get some extra practice on the machines…