We Limit Our Materials

  |   Agile, Blog, Industry News, Learning, & Education, Test Driven Development, WIKISPEED Shop & Manufacturing, Xtreme Manufacturing   |   2 Comments
A core XM (eXtreme Manufacturing) practice is to only use materials that can be inexpensively iterated (re-made) in less than a week, and then choose the fewest number of different materials / processes practical in order to build deep experience quickly.
Here’s the list of stuff to make the car:
1) aluminum, 6061-T6. stock shapes and extrusions with the fewest cuts or machining operations practical.
2) Carbon fiber for curvilinear shapes. Carbon wrapped over closed-cell foam.
3) White faux fur for all soft surfaces (this is especially awesome).
4) Flat, labeled AS1 safety glass for all glazing.
1A) extruded aluminum 6061-T6, 4″X4″ square tube, 1/8th inch thick wall. (for those outside the US, we can ship it to you or you can use a similar metric size like the team in New Zealand has done). Drilled and or cut.
1B) Aluminum plate, 6061-T6, 1/4″ thick. CNC waterjet cut.
1C) Bolt aluminum together with a single standardized fastener. 3/8ths, 24 thread, grade 8 bolt with 1″ OD steel washers 1/8th inch thick, and nylon lock nuts.
1D) Hinges are all 3/8ths 24 thread spherical rod end joints (heim joints) with a minimum radial load capacity of 4,000 lbs.
2A) to do it in less than a week, shape the foam then wrap it directly in carbon leaving the foam attached, or wrap the foam in syran wrap then carbon so that the foam may be re-used.
  • Christopher Rasch | Dec 6, 2014 at 2:18 AM

    Where do you source 6061-T6, 4″X4″ square tube, 1/8th inch thick wall tubing? Everything I’ve found in 4″x4″ is at least 3/16 (0.185″). Are you sure you didn’t mean 3/16th?

    • Chris Wallace | Dec 11, 2014 at 8:28 PM


      I forwarded your question to the Team Forum and received the following responses so far.

      4 x 4 x 0.125 inch wall, 6061 T6, 20 foot lengths, are stocked in Canada by Russell Metals.

      Joe has ordered several times from, but their website does not appear to list it right now. I’m not sure if that is an out-of-stock issue, or if they no longer carry that size.

      We have not ordered from this site so far, but they appear to list the product


      I order mostly from Coast Aluminum to save money, about half the price of Online Metals if I order 500lbs or more at a time.


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