2D Drawing of Rack and Pinion (Mechanical Movement #113)

My first attempt for this assignment was to draw mechanical movement 191 – the nautilus gear. The nautilus gear serves as a way to gradually increase speed (on its edge) as it spins. This turned out to be much more of a challenge than I anticipated because the nautilus gear is spiral shaped. The image trace of the hand drawing was not precise enough for me to use the shapes it produced, so I decided to draw the nautilus gear from the shape builder tools. Drawing a spiral in Illustrator with the same dimensions as the hand drawn image was incredibly difficult, but I finally was able to combine two ellipses to get the general shape.

However, an even greater challenge was adding gears to this spiral figure. Since it wasn’t linear or circular, I couldn’t use the built in pattern tools on Illustrator. Instead, the best solution I could figure out was drawing the shape of the gear cutout, copying it several times and rotating each cutout about the center of the gear and translating each of them to the edge of the gear. This turned out to be quite imprecise, as the gear teeth produced were very uneven. Although my reconstructed nautilus gear drawing was not too far off from the original drawing, it didn’t look like it would work too well.

I decided that I should probably learn how to make standard circular gears first, and moved on to making a 2D drawing of mechanical movement 113, which I had a lot more success with. Mechanical movement 113, the rack and pinion, works to convert rotational movement into rectilinear motion or vice versa. It’s components are a single circular gear (with bearings and a pin) that is stationary, and a moving rack with teeth that engage with the teeth of the gear. The rack is constrained to 2D linear motion by some sort of a track. Therefore, when the pinion spins the rack travels linearly, and likewise when the rack moves the pinion spins.

To convert this drawing into an Illustrator file, I began by doing an image trace of the animated image. I chose this figure rather than the original image because it was drawn a lot more precisely and obviously worked (given the animation), whereas the gears on the hand drawn original image were uneven and the rectangular shape didn’t look like it would work too well. The image trace of the animated figure was able to pretty well break up the parts of the  rack and pinion into their individual shapes. However, some of the precision was lost, and so I decided to reconstruct the drawing using the shape builder, pathfinder and transformation tools, and using the image trace as a template.

To create the gear, I drew concentric circles along with a star shape that had 16 points – one for ear of the gear teeth. I then used the pathfinder tools to cut away the outer points of the star and merge the gear teeth with the circular body of the gear.

To make the gears on the rack, I first drew a single gear tooth as a rectangular shape and used the direct selection tool to make it trapezoidal. I then used the transform tool to copy the shape and make a linear pattern.

This assignment definitely got me familiar with and comfortable using Illustrator. It allowed me to discover and use many of the different tools available as I tried creating each part a number of ways to figure out what techniques produced the best effects. Overall, I found that when creating technical drawings where precise dimensions and functionality matter, it’s better to fully reconstruct the drawing rather than simply do an image trace.

Here are the illustrator files for the nautilus gear (#191) 507mechanicalmovements_113-1qqlxyc and rack and pinion (#113) 507mechanicalmovements_191-u3z8uc.

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