Skillbuilder Mechanisms - Rack and Pinion

This project was completed as part of GE1501: Cornerstone of Engineering at Northeastern University. The objective was to explore mechanical motion systems by designing and prototyping a mechanism that converts rotational motion into linear motion.
Our goals were to:
Understand how rack-and-pinion systems function.
Learn and demonstrate AutoCAD drawing and laser cutting skills.
Apply engineering design process principles through iteration, testing, and reflection.
Strengthen teamwork, problem-solving, and fabrication abilities.

We designed and built a rack-and-pinion mechanism that transforms the rotational motion of a circular gear (pinion) into the linear motion of a straight gear (rack).
The pinion gear is rotated manually, and its teeth engage with those of the rack, pushing it back and forth.
The base structure was made from cardboard, supported by wooden sticks and breadboard materials.
The final design was laser-cut in AutoCAD to ensure proper alignment, symmetry, and motion smoothness.
The system demonstrates a core mechanical principle used in robotics, camera sliders, and drawer slides, where precise linear movement is needed

What We Tried That Didn’t Work:
The early prototype used a string as a connector, which caused misalignment and inconsistent movement.
Lack of a stabilizing base resulted in frictional drag and poor accuracy.
What Worked:
Switching to wooden sticks and hot glue improved structure and motion smoothness.
Adding a backboard aligned the rack and reduced friction.
Laser-cut design improved precision and repeatability.
Unique Aspects:
Our mechanism emphasized dimensional accuracy and guided motion using minimal materials.
Skills Learned:
Translating physical observations into AutoCAD geometry.
Testing mechanical efficiency through repeated design revisions.
Strengthening collaborative design workflow.

This project deepened our understanding of mechanical translation systems and the importance of testing before fabrication.
Seeing our final mechanism smoothly operate was rewarding; it combined engineering design, communication, and technical precision into one cohesive product