Exploded view of concept.

The Modern Protractor
Current protractors are often a single piece of plastic and in the shape of a half-circle. I find them cumbersome to use because I will have to measure the angle, mark a point, and then pull the protractor away to draw the line. And in the case that I want to draw an arc, the protractor does not allow for arbitrary radii lengths to be drawn easily.

The Project
As an independent project, I decided to design a more robust version of the protractor. The main feature of this protractor would be the ability to draw lines and arcs in one simple motion.

Assembled top view.
This new version of the protractor is in two pieces. The top piece, which holds a ruler, sits in a circular track so that it may rotate freely. In addition, there is a narrow channel in the center of ruler for a pencil or compass to fit inside.

Currently, it has not been built and tested. As a result, there may be some issues, such as the width of the channel on the ruler being too thin. In the future, I would like to add a clamp or stopper so that the track will not shift when drawing straight lines.

Ruler STL File |link|
Protractor Plate STL File |link|