Do you want to build a backhoe?

Welcome to CPW: Campus Preview Weekend, when we all pretend schoolwork doesn't exist and celebrate our prospective freshmen! The theme this year is "Kindergarten," which is a funny contrast to spring break's unofficial theme "Is College; No Parents"

I wanted to make a sandbox digger in the style of this instructable, out of dimensional lumber and prefrosh labor. The goal was to make a design on which prefrosh could learn how to use powertools (high error tolerance), but also have a fun, functional machine at the end of CPW.

Jennie and I sent in a design and safety proposal to our CPW chairs and to MIT's office of Environment, Health, and Safety. (EHS) Our proposed design looked like this:

EHS got back to us with various safety questions, and also requested extremely detailed drawings of our design and assembly process. I was going to make these anyway, since the plan was for prefrosh to do nearly all the construction (minus cutting wood). We sent in six pages of drawings in the style of LEGO blueprints.

Somewhere between making plans and starting construction, we decided to switch out bolts for 1/4" and 3/8" threaded rod, courtesy of MITERS.

Construction and assembly happened on the Saturday of CPW. Prefrosh learned the wonders of double-nut threading.

final product!

We discovered that 3/8" OSB (original plans called for 5/8") was not nearly structural enough to support our lazy susan turntable bearing, so we last-minute swapped them for 2x8 squares. We also ended up with creative supports for the 4x4 -> base connection.

But at the end of CPW, we had a working backhoe! Prefrosh built, Upperclassman tested.