8020 is an industrial prototyping extrusion made from aluminium. I used it here to construct a chopper by joining the extrusions with water-jet cut plates of 1/4inch aluminum.
Step 1: Choose and Design the Type of Bike Frame You Wish For
Here are some of the options we designed at an MIT IAP class in 2003.
The CAD files are all included in this step.
Step 2: Choose the Connecting Parts From the Part Library or Design Your Own.
These parts will be cut from 1/4 or 1/2inch thick aluminum plate using a water-jet.