The Trials of Travco

I'm taking a mechanical design class.  This is a hopelessly wide topic and so this is just an introduction.

The most fun part is also the most educational.  We work together in small groups that are in essence little design firms.  I was recently working with three other guys.  One of them being named Travis we dubbed ourselves Travco.

The assignment was to create a wrench that could tighten or loosen various sized bolts inside a tiny cramped space.  

We quickly came up with a variety of designs that we considered too easy.  The final design had 18 parts.  The whole thing was sketched out on paper, then drafted with Solidworks software.  The parts files were sent to a 3D printer.  Here's how things went.....

The wrench worked by having pulleys driven by a belt.  The hex cutouts matched the bolt head sizes.  A hand crank turned it.  There are two different cranks show below..human error, one was made with the wrong dimensions.

Obviously the metal part was not 3D printed.  In an effort to do things "real world" the design had some outsourced bushings made of Oil Lite brass.  It was my job to machine them to the right size.  And a pesky bit of work that was.

Finished product with belt installed.  A keen observer might note that the pulleys have been redone.  No human error this time, 3D printers just have more variation in final dimensions than you might expect.  The pulleys were done a second time with looser tolerances.

Final product in action.  The functional and entirely impractical Travco 
T-rench ready for mass production.  We are patiently waiting by the phone for that venture capitalist to call and offer to buy us out for millions of dollars.