Summary

This is a modular kit designed to be friendly to low-budget makers who want a way to quickly build structures such as bridges, without difficulty or hassle. Held together by pencils, with supplied clips for securing cardboard, these easy-print pieces will help you throw together a miniature bridge in no time at all. These can also be used for education in building sturdy structures, such that they do not easily collapse.

Print Settings

Printer Brand:

Printrbot

Printer:

Simple Black

Resolution:

Unknown

Infill:

15%

Notes:

The clip for the cardboard needs to be rotated 90 degrees such that the birds' eye view makes the piece look like an H, for lack of a better phrase.

For the main arms, rafts may not be required. I only use them because I have fairly routine adhesion problems. For the clips, however, the raft or a brim is highly recommended, as it has an extremely small base contact when oriented correctly. No piece requires supports.

Post-Printing

Just break off the raft/brim, if you used any, and you're done!

How I Designed This

This was designed in a program called Onshape. The length of the arm was set to be compatible with a Pythagorean triangle at 100 mm, center point to center point. The hole size was set such that it would accept the average wooden pencil snugly, so that pencils could be used as a connector. (Note: Wooden, hexagonal pencils seem to work best.) The slots in the main arm were added mainly for aesthetics. The clip was designed to fit into the recess of the arm, and serve as a universal clip. The longer, thicker jaws are designed to accommodate common cardboard well, and they serve as a perpendicular connector for attaching cardboard as facing.

Custom Section

Objectives

The objective of this project is to produce a supporting structure, similar to that of a side of a bridge, to plainly demonstrate the inherent strength of certain patterns of rigid bars. This lesson can then be proven learned by the students' construction of a long structure that would not otherwise be feasible without the supporting structure.

Audiences

This is project is targeted mainly to students in middle school and high school. The larger the group working, the better, as the process can become time consuming. Of course, there is no reason someone from outside one of these generalizations can't have fun with this kit!

Preparation

Students need to know the inherent advantages of triangles, which is quickly taught without difficulty. However, a significant amount of time needs to be set aside ahead of time to print all of the arms. Remember that each arm is only 100 mm from center point to center point. The larger the structure, the more arms that are going to be needed. Fortunately, they can be printed en masse. The clips, though still numerous, are required far less often, and no more than 20 should be needed for most small basic frame works.

Steps

The project is meant to teach students how to think constructively, and show them the advantages of certain designs and methods. The teacher should give a brief overview of the structural advantages of triangles, and then give the students an objective of creating a structure that can support a set amount of weight that also bridges a gap of a certain distance. Pencils should be provided by the dozens to the students, as the arms tend to accumulate many connectors. For the students to become more invested, have a small competition to see who can get the most weight-per-arm ratio supported in their design.

Results

The students should have acquired some sense of weight distribution, constructive thinking, and the skill to build a basic supporting structure. Assessment, in this scenario, is difficult to judge; this much more a pass/fail lesson than anything else. For more projects that can be done with the pieces, try building a structure that is reminiscent of one that can be found nearby or off of a Google Search or two.

Modular Pencil Construction Kit