How to Build a Toothpick Bridge

Building Toothpick Bridges is a common hobby that has no age limit. Building Toothpick Bridges is also a common school project giving to kids with the goal to build the strongest in the class. This article will cover the basics to building a simple strong Toothpick Bridge.

Difficulty:

Moderately Easy

Instructions

Things You'll Need

• Toothpicks, wood glue, razor blade

1. 

   First thing to do is hand draw out the main truss for the bridge on graph paper, using the squares on the graph to make the 45 degree angles needed for the design of the bridge in this article. When drawing the bridge truss you should mark every where the toothpicks start and end that way you can stagger the seems where doublers are used. [see picture in step-5 fig-2] The total length of your bridge is open to your needs and the height of the upper part of the bridge truss should be based off one full toothpick. The length of your bridge may have to be adjusted for the 45 degree cross braces to start and end to the width of the bridge.

2. 

   The bridge truss should be built in small parts to simplify the construction. To start building it run the bottom roll of toothpicks of the truss first, cut the point off the toothpick so that they are square, then lay them out to the line on the graph paper and glue them together. The toothpicks running down the center should be one full toothpick and there should be a odd number of them total, the first one should start in from the right or left at the measurement of the center toothpicks. [A 45 degree angle or a 12/12 pitch means for every 12" of RUN there is 12" of RISE] After the first toothpick the layout is 1/2 the measurement of the first measurement with it ending with the same measurement you started with.

3. 

   The lower truss, start by running the top roll of toothpicks be sure that the toothpicks for the roll will brake in the center of the bottom of the upper truss. Running the cross webbing in the center of the truss is a little tricky, building it on top of the graph paper helps a lot also building a small "jig" to cut the 45 degree angle on the toothpicks will help simplify the lower truss construction.

4. 

   After the glue on the upper and lower trusses has dried, glue them together adding in all the extra braces like seen in the drawing in this step. After the construction is finished repeat the steps above to construct as many main trusses as needed. [its best to build a few extra sets of trusses for testing]

5. 

   After the side trusses are built you will need to build the "floor and ceiling" of the bridge or the "top and bottom". These should be built with 2 toothpicks on the sides and centers, [fig-2] then 1 toothpick for each part of the cross webbing. Built one to the measurement of the bottom of the upper truss and one to the measurement of the top of the truss.